The Greek definition of ”perfect” is teleios.
Definition: perfect, (a) complete in all its parts, (b) full grown, of full age, (c) specially of the completeness of Christian character.
We are told to be perfect as our Father in heaven is perfect and that means we CAN since we can trust the word of Jesus. It doesn’t say that God can be perfect for us, or that we should only STRIVE to be perfect but we are told to BE perfect. So to start off it’s clear that we CAN become perfect but the question is what that means? Evidently it could not mean to have lived a completely sinless life, because Jesus told people who have sinned to be perfect, and they of course couldn’t be required to change their past in order to obey Jesus. The best way to find the meaning of to ”be prefect” is to find similar examples of the same word in Greek – see below. When we are cleansed from our sins in the blood of Jesus we are indeed perfect and complete. God looks at us as though we have never sinned and we ARE free of sins thanks to being forgiven. But this does not mean that we are still fine even if we would continue to get filthy, because that will only get us dirty once more and again in need of cleansing. If we live in sin, we are neither perfect or complete. So a christian who sins is not perfect, but a christian who is cleansed and walk in the light is perfect. God doesn’t ask for anything impossible from us. Can we be as merciful as our Father is merciful? Jesus says we can, and Zacharias and Elisabeth are examples of this:
Luke 6:35But love ye your enemies, and do good, and lend, hoping for nothing again; and your reward shall be great, and ye shall be the children of the Highest: for he is kind unto the unthankful and to the evil.36Be ye therefore merciful, as your Father also is merciful.
Luke 1:5 There was in the days of Herod, the king of Judaea, a certain priest named Zacharias, of the course of Abia: and his wife was of the daughters of Aaron, and her name was Elisabeth.6 And they were both righteous before God, walking in all the commandments and ordinances of the Lord blameless.
If you don’t believe we can be either perfect or merciful as our Father, what other verses don’t you trust in the Bible? Can we argue that the the following commands are impossible to obey?
Luke 17:4 And if he trespass against thee seven times in a day, and seven times in a day turn again to thee, saying, I repent; thou shalt forgive him.
Matt. 28:19Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost
The OT shows that people can be perfect as well (read my post about numerous righteous people who lived in the OT):
1 Ki 11:4 For it came to pass, when Solomon was old, that his wives turned away his heart after other gods: and his heart was not PERFECT with the LORD his God, AS WAS THE HEART OF DAVID his father.
Examples of verses where ”teleios” is used:
1 John 4:18There is no fear in love; but PERFECT love casteth out fear: because fear hath torment. He that feareth is not made PERFECT in love.
1 Corinthians 14:20Brethren, be not children in understanding: howbeit in malice be ye children, but in understanding be men.
Philippians 3: 15Let us therefore, as many as be PERFECT, be thus minded: and if in any thing ye be otherwise minded, God shall reveal even this unto you. 16Nevertheless, whereto we have already attained, let us walk by the same rule, let us mind the same thing.
Colossians 4:12Epaphras, who is one of you, a servant of Christ, saluteth you, always labouring fervently for you in prayers, that ye may stand PERFECT and complete in all the will of God.
James 1:4 Let endurance have its PERFECT work, that you may be PERFECT and complete, lacking in nothing.
1 Corinthians 2:6Howbeit we speak wisdom among them that are PERFECT: yet not the wisdom of this world, nor of the princes of this world, that come to nought
Romans 12:2 Don’t be conformed to this world, but be transformed by the renewing of your mind, so that you may prove what is the good, well-pleasing, and PERFECT will of God.
1 Corinthians 13:10But when that which is PERFECT is come, then that which is in part shall be done away.
Ephesians 4:13Till we all come in the unity of the faith, and of the knowledge of the Son of God, unto a PERFECT man, unto the measure of the stature of the fulness of Christ:
Colossians 1:28 whom we proclaim, admonishing every man and teaching every man in all wisdom, that we may present every man PERFECT in Christ Jesus;
James 1:17Every good gift and every PERFECT gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning.
James 1:25But whoso looketh into the PERFECT law of liberty, and continueth therein, he being not a forgetful hearer, but a doer of the work, this man shall be blessed in his deed.
Matthew 19:21 Jesus said to him, ”If you want to be PERFECT, go, sell what you have, and give to the poor, and you will have treasure in heaven; and come, follow me.”
James 3:2 For in many things we all stumble. If anyone doesn’t stumble in word, the same is a PERFECT man, able to bridle the whole body also.
Hebrews 9:11 But Christ having come as a high priest of the coming good things, through the greater and more PERFECT tabernacle, not made with hands, that is to say, not of this creation,
Hebrews 5:14But strong meat belongeth to them that are of FULL AGE, even those who by reason of use have their senses exercised to discern both good and evil.
Examples of people who were perfect in the Old Testament
Gen. 6:9 These are the generations of Noah: Noah was a just man and perfect in his generations, and Noah walked with God.
1 Kings. 15:14 But the high places were not removed: nevertheless Asa’s heart was perfect with the Lord all his days.
Job 1:8 And the Lord said unto Satan, Hast thou considered my servant Job, that there is none like him in the earth, a perfect and an upright man, one that feareth God, and escheweth evil?
2 Kings 23:25 And like unto him was there no king before him, that turned to the Lord with all his heart, and with all his soul, and with all his might, according to all the law of Moses; neither after him arose there any like him.
Hebrews 11:5 By faith Enoch was translated that he should not see death; and was not found, because God had translated him: for before his translation he had this testimony, that he pleased God.