that you put off, concerning your former conduct, the old man which grows corrupt according to the deceitful lusts, and be renewed in the spirit of your mind, and that you put on the new man which was created according to God, in true righteousness and holiness. (Ephesians 4:22–24)

Today’s big question: how do we change immoral behavior?

The answer might sound a little too easy: if you don’t want to be immoral then be moral. This is practical advice but there is another very important part to the equation. We need a great renewal.

Whenever we want to honor God with godly behavior, we can only do so through Christ by allowing Him to renew our minds and hearts. It is only in the strength of His Spirit that we can truly be dead to sin. We have to accept that we are not actually changing anything in our own strength. We must fully rely on the transforming power of Christ.

The combination of putting off our old self and putting on the new self in true repentance and God’s transforming power is the Lord’s formula for ongoing sanctification. In simple terms, sanctification means “setting apart.” This requires replacement. We replace secular thinking with God’s truth. We replace pagan influence with a desire for His Word. As Paul told us in Ephesians, we must put off the old man and put on the new.

Later in Ephesians 4 he gives us a great example. If you want to stop being a thief, you should get a job and start giving to others. You should replace taking with working for what you get and being generous with it. This is great, practical wisdom.

Humans are habitual sinners, so we need to become habitually disciplined in the strength of Christ to replace the old self. In Colossians, Paul tells us that good works in Christ (e.g., preaching the truth) can only be done in His strength. “To this end I also labor, striving according to His working which works in me mightily” (Colossians 1:29).

Living a sanctified life is not easy, but it is possible for anyone in Christ. However, we cannot take for granted that we will stop sinning just because we claim Christ. He requires us to battle, repent, and replace in His strength. He already has obtained the victory for us, so even though replacing immoral behavior with moral behavior seems so difficult, we are not without ultimate hope of victory through Christ.  http://www.answersingenesis.org/articles/2011/04/07/change-immoral-behavior