There is a cosmic war. No one is exempt. Before conversion we fought against God in the army of hell. Now that we have been converted, we are fighting in the army of Heaven, against our old allegiances. Salvation has brought deliverance, but it has not yet brought complete rest. As a Christian, you should not be surprised by the conflict you will experience.
The New Birth Changes Our Disposition to Sin.
Jesus explained the act of God saving a sinner from sin as the new birth. He said to a very religious Nicodemus, “Most assuredly, I say to you, unless one is born again, he cannot see the kingdom of God” (John 3:3). The new birth is a spiritual birth that begins a new spiritual life, a life in concert with God rather than opposed to Him.
If you have experienced this second birth you have undergone a change in disposition. You have received a new nature with new motivations. Prior to conversion you loved sin, but after the power of God transformed your heart you love holiness. And even though you may not consider yourself very holy, you do have holy inclinations that are opposed to the unholy conduct you once lived.
A man was converted who was quite bold in his sins. One of his friends said to him, “I feel sorry for you. You now have to go to church, pray and read the Bible all the time. You no longer go to the nightclubs, get drunk, or enjoy the girls.” The new Christian said, “I do get drunk every time I want to. I do go out when I want to. It’s just that the Lord took the 'want to' out of me and I don’t want to anymore.”