It is a fact, and always was, that man cannot go through life sinless, if one man could do it Christ would not have to have been made flesh to be the perfect Lamb.
Any man that say's they are sinless (before or after Christ) is a liar.
1 John 1:10 (KJV)
10 If we say that we have not sinned, we make him a liar, and his word is not in us.
Interesting thought. Now add this to the thought...
Rom 4:15 Because the law worketh wrath: for where no law is, there is no transgression.
Rom 5:13 (For until the law sin was in the world: but sin is not imputed when there is no law.
Anyone who thinks there is salvation in the old law is in fact the Legalistic and nullifies the Cross.
Salvation was never even promised under the Old Covenant.
Like before the Law, Abraham did sin, but because he did his best to continually obey God he was counted Righteous.
He sinned because he broke the law. The law has been in effect since the Garden.
Like Abraham, and After Christ, man will still sin, being "in Christ" will not change that, but if we have the same "obedient faith" that Abraham had to God, a true Christian will be counted Righteous by obeying Christ, during the Mosaic law sacrifice rolled back sin for but a year, but Obeying ALL of Christ commands, and continuing in "obedient faith" the blood of Christ will continually wash away sin accounting righteousness to the man as long as he (like Abraham) keep "obedient faith" (we have to work at it, the works James speaks of)
Again, I find this very interesting. Yet, you tell us not to...
Mat 19:17 And he said unto him, Why callest thou me good? there is none good but one, that is, God: but if thou wilt enter into life, keep the commandments.
Mat 19:18 He saith unto him, Which? Jesus said, Thou shalt do no murder, Thou shalt not commit adultery, Thou shalt not steal, Thou shalt not bear false witness,
Mat 19:19 Honour thy father and thy mother: and, Thou shalt love thy neighbour as thyself.
Joh 14:15 If ye love me, keep my commandments.
Joh 14:21 He that hath my commandments, and keepeth them, he it is that loveth me: and he that loveth me shall be loved of my Father, and I will love him, and will manifest myself to him.
Joh 15:10 If ye keep my commandments, ye shall abide in my love; even as I have kept my Father's commandments, and abide in his love.