"For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live." (Romans 8:13)
To mortify something means to put it to death. Paul taught in our text and in other passages that the "deeds of the body," or its fleshly actions and appetites, all that pertains "to the old man," should be mortified, or put to death.
This mortification is first of all judicial--Christ having been put to death in our stead. "Our old man is crucified with him, that the body of sin be destroyed, that henceforth we should not serve sin" (Romans 6:6).
But the mortification must not stop there, with only a positional death. It must also be an actual mortification in practice, for "they that are Christ's have crucified the flesh with its affections and lusts. If we live in the Spirit, let us also walk in the Spirit" (Galatians 5:24, 25). "For as ye have yielded your members servants to uncleanness and to iniquity unto iniquity; even so now yield your members servants to righteousness unto holiness" (Romans 6:19).
Elsewhere, Paul identifies specific deeds and attitudes which must be mortified. "Mortify therefore your members which are upon the earth; fornication, uncleanness, inordinate affection, evil concupiscence |or evil desires|, and covetousness" (Colossians 3:5). The first four listed will be recognized as various forms of sensual sins, indicating how detrimental this category of sin is to spiritual life. The fifth is covetousness, or inordinate love of money and material things. These five comprise deadly sins to men and women of any historical age--particularly our own. If they are not put to death, they bring death, "for which things' sake the wrath of God cometh" (v. 6).
The choice is clear! It will be either death to the flesh, or death to the spirit. JDM