1Jo 1:8 If we say that we have no sin, we deceive ourselves, and the truth is not in us.
Rom 3:23 For all have sinned, and come short of the glory of God;
We all have sin. We are not “perfect” because of the fact that we have not sinned, or do not sin. We are made perfect through the blood of Jesus Christ. If a person is a faithful believer, Jesus makes him/her perfect. It’s not through any effort we can make to refrain from sin, that is not possible.
Rom 3:24 Being justified freely by his grace through the redemption that is in Christ Jesus:
Rom 3:25 Whom God hath set forth [to be] a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God;
1Jo 1:7 But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin.