Read Romans 7:7-14

So the trouble is not with the law, for it is spiritual and good. The trouble is with me, for I am all too human, a slave to sin. - Romans 7:14 (NLT)

God has given us a conscience, which often prompts us to do right and avoid wrong. But our sinful human nature resents the outside direction of the law, and chooses to disobey. Only the power of God’s Spirit within us can counteract that.