There are some who claim that they do not sin. Obviously, they are deceiving themselves when they do that.

We all sin and fall short of God's glory. So we must all confess our sins, so that God who is faithful and just may forgive us our sins.

This is really the only way to live, it is the only way to give glory to God. Those who say that they have no sin are essentially calling God a liar, and they do not know Him, and have not found the truth.