The KJV doesn’t describe God’s covenants as “eternal” covenants, but rather as “everlasting” covenants (16 times in KJV), and this is a translation from the Hebrew word “olam”, which apart from “eternal” can mean “forever“, and many compound this with the phrase “throughout their generations”.
With Abraham, the sign of the covenant between him and God was circumcision. Salvation would not continue if at some point men decided they did not need to circumcise their male children. Under Moses, the sign of the covenant was the Sabbath day, with the 10 commands being the covenant written out and placed in the Ark – representing the presence of God with them. Salvation would not continue if the Israelites broke those important commandments – without repenting or making an animal sacrifice. Water baptism is the sign of the new covenant, and the signs in the old covenants were completed in Christ. We are to be circumcised in heart and our Sabbath rest is in him, but we must hold to the commitment we made in the new covenant. The significance of the water baptism is our agreeing with God to keep the old man buried and to walk in the newness of life. If we still have sin that we are aware of and refuse to deal with, then sins are not taken away at all and we are in trouble. Modern false teachings have removed all fear of God and eternal judgment of those with sin, by teaching a false hope, a false gospel, and a false sense of security for those with unrepentant sins.
Ex. 31:12 And the Lord spake unto Moses, saying,13 Speak thou also unto the children of Israel, saying, Verily my sabbaths ye shall keep: for it is a sign between me and you throughout your generations; that ye may know that I am the Lord that doth sanctify you.14 Ye shall keep the sabbath therefore; for it is holy unto you: every one that defileth it shall surely be put to death: for whosoever doeth any work therein, that soul shall be cut off from among his people.15 Six days may work be done; but in the seventh is the sabbath of rest, holy to the Lord: whosoever doeth any work in the sabbath day, he shall surely be put to death.16 Wherefore the children of Israel shall keep the sabbath, to observe the sabbath throughout their generations, for a perpetual covenant.17 It is a sign between me and the children of Israel for ever: for in six days the Lord made heaven and earth, and on the seventh day he rested, and was refreshed.
An everlasting covenant?
Genesis 17:7 And I will establish my covenant between me and thee and thy seed after thee in their generations for an everlasting covenant, to be a God unto thee, and to thy seed after thee.—13 He that is born in thy house, and he that is bought with thy money, must needs be circumcised: and my covenant shall be in your flesh for an everlasting covenant.—19 And God said, Sarah thy wife shall bear thee a son indeed; and thou shalt call his name Isaac: and I will establish my covenant with him for an everlasting covenant, and with his seed after him.
Leviticus 24:8 Every sabbath he shall set it in order before the Lord continually, being taken from the children of Israel by an everlasting covenant
Numbers 25:13 And he shall have it, and his seed after him, even the covenant of an everlasting priesthood; because he was zealous for his God, and made an atonement for the children of Israel
1 Chronicles 16:17 And hath confirmed the same to Jacob for a law, and to Israel for an everlasting covenant,
Isaiah 55:3 Incline your ear, and come unto me: hear, and your soul shall live; and I will make an everlasting covenant with you, even the sure mercies of David.
Isaiah 61:8 For I the Lord love judgment, I hate robbery for burnt offering; and I will direct their work in truth, and I will make an everlasting covenant with them.
Jeremiah 32:40 And I will make an everlasting covenant with them, that I will not turn away from them, to do them good; but I will put my fear in their hearts, that they shall not depart from me.
Ezekiel 16:60 Nevertheless I will remember my covenant with thee in the days of thy youth, and I will establish unto thee an everlasting covenant.
Ezekiel 37:26 Moreover I will make a covenant of peace with them; it shall be an everlasting covenant with them: and I will place them, and multiply them, and will set my sanctuary in the midst of them for evermore.
Hebrews 13:20 Now the God of peace, that brought again from the dead our Lord Jesus, that great shepherd of the sheep, through the blood of the everlasting (aiónios Strong’s 166) covenant (diathéké Strong’s 1242)
Greek Aiónios. Definition: age-long, and therefore practically eternal, unending; partaking of the character of that which lasts for an age, as contrasted with that which is brief and fleeting.
An everlasting covenant can be broken
God’s covenant has shown to be broken through rebellion – contrary to God’s will.
Genesis 17:14 And the uncircumcised man child whose flesh of his foreskin is not circumcised, that soul shall be cut off from his people; he hath broken my covenant.
Leviticus 26:15 And if ye shall despise my statutes, or if your soul abhor my judgments, so that ye will not do all my commandments, but that ye break my covenant:—44 And yet for all that, when they be in the land of their enemies, I will not cast them away, neither will I abhor them, to destroy them utterly, and to break my covenant with them: for I am the Lord their God.
Psalm 55:20 He hath put forth his hands against such as be at peace with him: he hath broken his covenant.
Deuteronomy 31:16 And the Lord said unto Moses, Behold, thou shalt sleep with thy fathers; and this people will rise up, and go a whoring after the gods of the strangers of the land, whither they go to be among them, and will forsake me, and break my covenant which I have made with them.—20 For when I shall have brought them into the land which I sware unto their fathers, that floweth with milk and honey; and they shall have eaten and filled themselves, and waxen fat; then will they turn unto other gods, and serve them, and provoke me, and break my covenant.
Isaiah 33:8 The highways lie waste, the wayfaring man ceaseth: he hath broken the covenant, he hath despised the cities, he regardeth no man.
Jeremiah 11:10 They are turned back to the iniquities of their forefathers, which refused to hear my words; and they went after other gods to serve them: the house of Israel and the house of Judah have broken my covenant which I made with their fathers.
Jeremiah 33:20 Thus saith the Lord; If ye can break my covenant of the day, and my covenant of the night, and that there should not be day and night in their season;21 Then may also my covenant be broken with David my servant, that he should not have a son to reign upon his throne; and with the Levites the priests, my ministers
Ezekiel 16:59 For thus saith the Lord God; I will even deal with thee as thou hast done, which hast despised the oath in breaking the covenant.
Ezekiel 17:15 But he rebelled against him in sending his ambassadors into Egypt, that they might give him horses and much people. Shall he prosper? shall he escape that doeth such things? or shall he break the covenant, and be delivered?—18Seeing he despised the oath by breaking the covenant, when, lo, he had given his hand, and hath done all these things, he shall not escape.19 Therefore thus saith the Lord God; As I live, surely mine oath that he hath despised, and my covenant that he hath broken, even it will I recompense upon his own head.
Ezekiel 44:7 In that ye have brought into my sanctuary strangers, uncircumcised in heart, and uncircumcised in flesh, to be in my sanctuary, to pollute it, even my house, when ye offer my bread, the fat and the blood, and they have broken my covenant because of all your abominations.
Judges 2:1 And an angel of the Lord came up from Gilgal to Bochim, and said, I made you to go up out of Egypt, and have brought you unto the land which I sware unto your fathers; and I said, I will never break my covenant with you.
Zechariah 11:10 And I took my staff, even Beauty, and cut it asunder, that I might break my covenant which I had made with all the people.
The Hebrew Festivals were often referred to as being eternal: The Sabbath is called an “eternal covenant” in Exodus 31:16-17. Passover is called eternal in Exodus 12:13,17, and 13:10. Shavuot or “Pentecost” is identified as such in Leviticus 23:21, Yom Kippur (Day of Atonement) in Leviticus 16:29, 31, 34 and 23:31. And Succot or “booths” is likewise identified as such in Leviticus 23:41. The Levitical Priesthood and sacrificial system is identified as eternal in the Hebrew Scriptures. The Priesthood itself is described as an eternal covenant in Numbers 25:12,13, see also Exodus 29:9 and 40:15. Likewise of the Priestly vestments in Exodus 28:29,43. Regarding Temple vessels we see the basin being commanded forever in Exodus 30:21 the Menorah in Leviticus 24:3 and the trumpets in Numbers 10:8. The Shewbread is described as eternal in Leviticus 24:8 and scattered indications of eternal sacrifices such as in Leviticus 7:36 (and those sacrifices implicitly included in the festivals).
Lexical/Biblical data concerning OLAM
Olam doesn’t mean “continually in force throughout infinite time, no matter what happens to the world” and nor is it irreversible or something God cannot put to an end, should conditions change as to warrant such a change. Meaning:
“Long duration, antiquity, futurity: a. indefinite futurity , c. prep. for ever , always (= during the lifetime ); slave for ever ; serve for ever ; redemption at any time; ever pregnant (womb); of persecutors of Jeremiah; always at ease; may the king live always ; so of the pious; I will sing for ever (as long as I live); other emotions and activities continuous through life. b. = continuous existence , (1) of things: the earth; other phr., heavens and contents, ruined cities, ruined lands or a witness for ever , in a book; (2) of nations: Babylon, of Judah; (3) families; the dynasty of Saul; house of Eli; (4) national relations: continual enmity ; of exclusion from; various relations; perpetual reproach , of dynasty of David, families ; of God’s covenant: everlasting covenant ; covenant with Noah ; God remembers it; will not break it, e. of God’s laws;temple to bear God’s name; consecrated; its ceremonies; Levit. priesthood; Aaronic priesthood. f. of God’s promises: his word; promised dynasty of David; of holy land; given, inherited; dwelt in; other blessings; Jerus. to abide” [BDB]
2 King. 17:37 And the statutes, and the ordinances, and the law, and the commandment, which he wrote for you, ye shall observe to do for evermore; and ye shall not fear other gods.
“For evermore” could be viewed as “every day” or an idiom for eternal/always.
Ps. 112:3 Wealth and riches shall be in his house: and his righteousness endureth for ever.
That neither the Hebrew nor the Greek word in itself contains the idea of endlessness is shown both by the fact that they sometimes refer to events or conditions that occurred at a definite point in the past, and also by the fact that sometimes it is thought desirable to repeat the word, not merely saying “forever” but “forever and ever”. In Gen 6:4 it points to the time shortly before the flood. None of these past references has in it the idea of endlessness or limitlessness, but each points to a time long before the immediate knowledge of those living. (THAT II, p. 230) J. Barr (Biblical Words for Time (’1969), p. 73) says, “We might therefore best state the “basic meaning” as a kind of range between ‘remotest time’ and ‘perpetuity’”.
The New Covenant of Jeremiah 31 was seen as a covenant superseding the Mosaic covenant. The Hebrew Bible sees these two covenants as being in contrast (this New covenant related to the “Old” Covenant of Sinai), and one major difference is that ONLY the Newer Covenant is “olam”. The Mosaic covenant is never called an “olam berith” in the Hebrew Bible (unlike other covenants).
Ezekiel and second Isaiah look forward to an everlasting covenant between God and the nation ( Ezek 16:60 ; Isa 55:3 ; 61:8) which they describe elsewhere as a covenant in which God’s Spirit will indwell the people ( Ezek 36:27–28 ; Isa 59:21 ). Malachi’s “messenger of the covenant” is cast as a priestly figure ( Mal 3:1 ; cf. 2:1–9 ). Ezekiel 37 again speaks of the great blessings to be enjoyed by the people of God, including cleansing, walking in God’s statutes, recognition as God’s people, and he says of this era of blessings: “I will make a covenant of peace with them; it shall be an everlasting covenant with them” ( v 26). Other important foreshadowings of the new covenant are found in Isa. 54:10 ; 55:3 ; 59:21 ; 61:8 ; Hos. 2:18–23 ; Mal. 3:1–4. Jeremiah’s words imply the receiving of a new heart by the people, as is expressly promised in the parallel prophecy of Ezek. 11: 19 and 36:26.
The text doesn’t suggest that God will close his eyes and randomly give people a new heart regardless of their own actions, and even if they haven’t even sought him or repented for their sins. Neither does it say that those who are given new hearts will be programmed to do God’s will without any effort of their own and with no failure to do so. It’s rather clear that there are no people living today who are programmed to always do God’s will and who therefore are not affected by any temptations since they are predestined to never sin again. However, if we consider that the holy Spirit is viewed as our guide and Helper, and someone who can lead us on the right path provided that we allow ourselves to be led by Him, then the prophesies in Jeremiah, Ezekiel and Isaiah, about the future everlasting covenant might rather be a reference to the new covenant with Jesus Christ – whose death enabled us to get the holy Spirit as a sign/mark/seal and to be placed within us (which is what Hebr. 8-10 suggests). We will be sealed “unto (FOR) the day of redemption”, so the seal is the initial phase on our journey to finally enter the eternal kingdom of God. A guarantee note or a seal can of course be broken if the conditions are not met, but if we allow ourselves to walk in the Spirit, we will not fulfill the lust of our flesh. Especially the book of Hebrews talk a lot about the new covenant in Jesus Christ, which concerns the idea that we can have the law in our hearts.
Romans 8:1 There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit.
Galatians 5:16 This I say then, Walk in the Spirit, and ye shall not fulfil the lust of the flesh.
Hebrews 8:8 For finding fault with them, he saith, Behold, the days come, saith the Lord, when I will make a new covenant with the house of Israel and with the house of Judah:9 Not according to the covenant that I made with their fathers in the day when I took them by the hand to lead them out of the land of Egypt; because they continued not in my covenant, and I regarded them not, saith the Lord.10 For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people
Hebrews 9:8 The Holy Ghost this signifying, that the way into the holiest of all was not yet made manifest, while as the first tabernacle was yet standing: 9 Which was a figure for the time then present, in which were offered both gifts and sacrifices, that could not make him that did the service perfect, as pertaining to the conscience;—11 But Christ being come an high priest of good things to come, by a greater and more perfect tabernacle, not made with hands, that is to say, not of this building;—15 And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance.16 For where a testament is, there must also of necessity be the death of the testator.17 For a testament is of force after men are dead: otherwise it is of no strength at all while the testator liveth.
Hebrews 10:7 Then said I, Lo, I come (in the volume of the book it is written of me,) to do thy will, O God.—15 Whereof the Holy Ghost also is a witness to us: for after that he had said before,16 This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them;—19 Having therefore, brethren, boldness to enter into the holiest by the blood of Jesus,20 By a new and living way, which he hath consecrated for us, through the veil, that is to say, his flesh;21 And having an high priest over the house of God;22 Let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience, and our bodies washed with pure water.-–28 He that despised Moses’ law died without mercy under two or three witnesses:29 Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace?
Read more about the prophesies which are fulfilled by means of Jesus Christ and the holy Ghost.
Isa. 55:3 Incline your ear, and come unto me: hear, and your soul shall live; and I will make an everlasting covenant with you, even the sure mercies of David.
Ezek.36:25 Then will I sprinkle clean water upon you, and ye shall be clean: from all your filthiness, and from all your idols, will I cleanse you.26 A new heart also will I give you, and a new spirit will I put within you: and I will take away the stony heart out of your flesh, and I will give you an heart of flesh.27 And I will put my spirit within you, and cause you to walk in my statutes, and ye shall keep my judgments, and do them.
Jeremiah31:31 Behold, the days come, saith the Lord, that I will make a new covenant with the house of Israel, and with the house of Judah:32 Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the Lord:33 But this shall be the covenant that I will make with the house of Israel; After those days, saith the Lord, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people.
Jeremiah 50:4 In those days, and in that time, saith the Lord, the children of Israel shall come, they and the children of Judah together, going and weeping: they shall go, and seek the Lord their God.5 They shall ask the way to Zion with their faces thitherward, saying, Come, and let us join ourselves to the Lord in a perpetual covenant that shall not be forgotten.6 My people hath been lost sheep: their shepherds have caused them to go astray, they have turned them away on the mountains: they have gone from mountain to hill, they have forgotten their restingplace.
Ezek 16.57 Before thy wickedness was discovered, as at the time of thy reproach of the daughters of Syria, and all that are round about her, the daughters of the Philistines, which despise thee round about.58 Thou hast borne thy lewdness and thine abominations, saith the Lord.59 For thus saith the Lord God; I will even deal with thee as thou hast done, which hast despised the oath in breaking the covenant.60 Nevertheless I will remember my covenant with thee in the days of thy youth, and I will establish unto thee an everlasting covenant.61 Then thou shalt remember thy ways, and be ashamed, when thou shalt receive thy sisters, thine elder and thy younger: and I will give them unto thee for daughters, but not by thy covenant.62 And I will establish my covenant with thee; and thou shalt know that I am the Lord:63 That thou mayest remember, and be confounded, and never open thy mouth any more because of thy shame, when I am pacified toward thee for all that thou hast done, saith the Lord God.
Isa. 42: 6 I the Lord have called thee in righteousness, and will hold thine hand, and will keep thee, and give thee for a covenant of the people, for a light of the Gentiles;7 To open the blind eyes, to bring out the prisoners from the prison, and them that sit in darkness out of the prison house.
Jesus applied this to Himself, early in His ministry to Israel.
You can read further in this article from christian thinktank