For if you live after the flesh, you shall die: but if you through the Spirit do put to death the deeds of the body, you shall live. (Rom 8:13)
Within mankind there is a tension. It is a tension between the spirit and the flesh. Within this tension we need to make our choice. Either obeying the lusts of the flesh, or live a life well pleasing to God. It takes some effort as we need to put to death the old nature of sinfulness. We need to deal ruthlessly with all jealousy, anger, strife, bitterness etc. We need to bring all such things to the foot of the cross, and lay it bare. As we confess our sins, He is faithful and just to forgive us and to cleanse us from all unrighteousness.