The Christian life is a life of change. When God saved us, we changed spiritually in a most dramatic way—we transformed from spiritual deadness to spiritual life (Ephesians 2:1-5). Since then, we are changed people (2 Cor 5:17), in a permanent process of change (Phil 2:12-13; Rom 12:2). This continual process of change is a wonderful change of mental renewal as we put off everything that reeks of sin, and put on everything that reflects the righteousness of Christ (Eph 4:22-24).
However, as inherently amazing as this continual change in our lives is, and as obviously wonderful as the outcome is, we find it very difficult to change sinful habits. The pull of temptation is strong. The pride in our hearts makes us hard-headed. Humility is just so very difficult in the moment when it is really needed.
God therefore does not leave us without hope, but provides helps in numerous ways. Here are some of the ways God has provided for us to overcome the difficulties of changing sinful habits.
First, learn to confess well. The example in Judges 10:10 starts well with acknowledging one’s sinful habit in appropriately specific terms. Not just “Sorry, I was wrong” but “Sorry, I sinned by again doing ___________”. After a rebuke from God for incomplete confession, Judges 10:15 completes the confession with an acknowledgement that any punishment would be fair, and a pleading for grace and mercy. True confession therefore begins with a specific acknowledgement of the sin and its just punishment, but then pleads for the mercy of being delivered from the guilt of that sin by the one whom you sinned against. Then, if he/she forgives, accept it joyfully (Ps 103:10-12).
Then, learn how to change completely. This is where Romans 12:2 is a helpful summary, and the longer explanation in Ephesians 2:22-24 with the examples in the rest of the chapter is very helpful. To change completely we must identify the specific sin we long to stop (Eph 4:22), we must search the Scriptures to change the way we think (Eph 4:23) about sin, ourselves, God and others, and we must define very clearly what righteous actions we want to practise (Eph 4:24) in the moments when tempted to do the old sin again. Then we will change as God intended us to change, literally, as 2 Corinthians 3:18 says “from one degree of glory to another”
And lastly, enlist all the help you can. Go and get some counsel from those much more spiritual than you (Gal 6:1). Enlist even the help of the one you normally sin against as he/she will spot the sin and sense the need for change even more than you probably do (Matt 18:15). Do not grow weary with the intensity of the beginning of the fight, for their is great reward (Gal 6:8-9).