The term "flesh" is used in different meanings in the Bible:
a) as an expression of physicality or humanity, which is inextricably linked to our life on earth. Examples: “the Word became flesh” (Jn 1:14); “all flesh will see the salvation of God” (Lk 3:6); “but what I now live in the flesh...” (Gal 2:20);
b) Since the fall of man, flesh has been the instrument and vessel of sin dwelling in man. In this sense, "flesh" has become the epitome of the sinful nature. It is the nature of the old man. Therefore, the unbeliever is characterized as being "in the flesh" because he is dominated by the impulses of his sinful nature. Even as believers who have been born again, we still have the flesh with its evil impulses in us as long as we are still on earth. We are therefore called upon to live in the power of the Spirit so that the flesh with its sinful impulses does not take effect in us (Gal 5:16ff). We have died to sin (the flesh), but the flesh lives on. When we nourish it, it shows itself (Rom 13:14). The flesh is incorrigibly evil (John 3:6). That is why God cannot forgive the old nature but must judge it. He did this on the cross (Rom 8:3). As believers, we do not have to give in to the desires of the flesh but are freed from the compulsion to sin.
