Romans 8:5

Those who are living according to the flesh set their minds on the things of the flesh (which gratify the body), but those who are living according to the Spirit (set their minds on) the things of the Spirit (His will and purpose).

We must school our minds to the things of the Spirit and cast down and out anything against the Spirit of God. It is the only way to keep our peace and to walk out our call here. The practice and time are worth the effort. A sound mind takes a sound faith, and the flesh is an adversary to both.