A selection of verses telling us that we all continually sin:
20 Surely there is not a righteous man on earth who does good and doesn’t sin.
23 for all have sinned, and fall short of the glory of God;
12 Therefore as sin entered into the world through one man, and death through sin; so death passed to all men, because all sinned.
2 For we all stumble in many things. Anyone who doesn’t stumble in word is a perfect person, able to bridle the whole body also.
8 If we say that we have no sin, we deceive ourselves, and the truth is not in us. 9 If we confess our sins, he is faithful and righteous to forgive us the sins, and to cleanse us from all unrighteousness. 10 If we say that we haven’t sinned, we make him a liar, and his word is not in us.
These chapters have links to this theme: