"We are sin?"
No, Jesus was made SIN for us when He bore our punishment on the cross doing away with our original sin nature (justification). However we live in a fallen world and because of our human nature we do sin and Hebrews tells us if and when we do sin we have an advocate with the Father, Jesus Christ (sanctification).
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. If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, he is faithful and just to forgive us [our] sins, and to cleanse us from all unrighteousness. If we say that we have not sinned, we make him a liar, and his word is not in us."
OK, sorry, I misread your first post. You didn't say "we are sin" but "we sin".
Regards