Romans 8:13
For if you live according to the flesh, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live.
The instruction is to put to death the misdeeds of the body BY THE SPIRIT.
If we confess our sins, it is not self effort, it is God who cleanses us from all misdeeds, wrong desires.
If we use will power, it is self effort. Although we can stop ourselves from sinning, the desire to sin, to steal , still rages on within our body.
But if we hear with faith, that God will indeed remove those desires, He is faithful to do just that, by giving His Spirit,
Galatians 3:
11Clearly no one who relies on the law is justified before God, because “the righteous will live by faith.”
f12The law is not based on faith; on the contrary, it says, “The person who does these things will live by them.”
g13Christ redeemed us from the curse of the law by becoming a curse for us, for it is written: “Cursed is everyone who is hung on a pole.”
h14He redeemed us in order that the blessing given to Abraham might come to the Gentiles through Christ Jesus, so that by faith we might receive the promise of the Spirit.
Because He promised to do it, and God's righteousness requires Him to keep His promises.
Do you believe that God will keep His promise to cleanse you from all righteousness if you ask Him to, because it is written in the Bible?