There is a difference between “self-control” and “will power.”
At this time in my life I am just coming to understand the difference. While I don’t think I have a full understanding of the subject I would like to relate what I am learning.
Self-control is a fruit of the Spirit; will power is a work of the mind. That is not to mean that will power is bad, just that there is no life or not much good that it does for our spiritual growth. Spiritual growth would naturally come from relying on and trusting in the Spirit of God and not from our own works no matter how good they might appear.
(Gal 5:23 NIV) gentleness and self-control. Against such things there is no law.
(2 Pet 1:6 NIV) and to knowledge, self-control; and to self-control, perseverance; and to perseverance, godliness;
Someone might be angry with someone and will power might prevent them from physically abusing or verbally abusing that person but it would not prevent the desire to abuse. The fruit of self-control would not only prevent the abuse but would prevent the desire.
I’m not saying that will power doesn’t have a place in our lives. What I am saying is it would be easier to stop a practice if there was no desire for the practice. Self-control comes from having purpose other than fulfilling the desires of the flesh. When our purpose is of God and in God our desire is directed towards things that are edifying to the life of Christ in us and self-control naturally flows from that purpose.
When we are concerned with self then the desires of the flesh become our purpose and the battle that wages in the Christian then calls for abstinence and shear will power can have a self glorifying effect but not spiritually edifying effect.
I may very well be able with shear will power to clean up my life from all outward sin. What good is it if the result is pride? I may say to God be the glory, but if in my own mind I take credit, it is still pride and pride goes before a fall. So we are doomed to a miserable existence unless through spiritual growth we grow in the reality of our relationship with the Lord, and rest from our own labors.
When I quit smoking and drinking it was not because I tried to quit. I began seeking and developing my relationship with the Lord. Those things fell away as a result; self-control was the fruit of a relationship with him.
Now if someone had been there pointing out my faults and I had got my focus off of the Lord and on those things, then my relationship would have suffered and I would have been fighting with will power. I would probably still be fighting with those things.