The Spirit war against the flesh- what is it?
Now, life becomes complicated once we are renewed by the Holy Spirit (when we become a Christian); now we have two principles at war within ourselves: the old inclinations and the new inclinations.
The old inclination is against God, and the new inclination is to obey God and to do that which is pleasing to him. In this Galatians passage, Paul discusses the ongoing battle that all Christians experience. He admonishes us at one point and says, “Follow the new principle; follow the new spirit, not the old pattern that was characteristic of your original state of fallenness.”
He’s not saying that your physical body is at war with your soul, but that your natural inclinations are at war with the transformation toward which the Holy Spirit is constantly moving you as a child of God. And that does involve a decision and an act of the will.