Even though we're Christians we still sin. As John said,

(1 John 1:8-9 NIV) If we claim to be without sin, we deceive ourselves and the truth is not in us. {9} If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.

The Bible refers to us as blameless.

(Ephesians 1:2-6 NIV) Grace and peace to you from God our Father and the Lord Jesus Christ. {3} Praise be to the God and Father of our Lord Jesus Christ, who has blessed us in the heavenly realms with every spiritual blessing in Christ. {4} For he chose us in him before the creation of the world to be holy and blameless in his sight. In love {5} he predestined us to be adopted as his sons through Jesus Christ, in accordance with his pleasure and will-- {6} to the praise of his glorious grace, which he has freely given us in the One he loves.