“Therefore prepare your minds for action; discipline yourselves; set all of your hope on the grace that Jesus Christ will bring you when he is revealed.”–1 Peter 1:13, NRSV
The hymn says, “Onward, Christian soldiers, marching as to war.” And the war is between our ears. We can’t avoid it. We have no human enemies! As Christians, our reborn spirit desires to serve Christ; our old sin nature desires to please our own flesh. Did you get mad when you read, “we have no human enemies?” That was the voice of your sin nature and its desire to get even with someone.
What about enemies of our country? The U.S. is in two wars now, and with no reflection on their rightness or wrongness intended, they have nothing to do with Christian warfare.
All of our words and actions begin as thoughts, and so our minds are continually torn between the reborn spirit and the old sin nature. As the latter is older and more familiar, it has an advantage. How can our minds choose the urging of the spirit over the urgings of the flesh? By the hard work of developing self-discipline.
The rewards of the flesh are immediate, and the troubles from bad choices play out over time. God gives grace every day to help us overcome our flesh, but it is on the long-term grace, which is not yet revealed, that we fix our hope as an incentive to self-discipline and to turning the battle in our minds in favor of our re-born spirit.