Before we accepted Jesus as Lord, Savior, and God by His terms, we had an old nature, an "old self" (Eph 4:22). "We lived at the level of the flesh" (Eph 2:3); we had "old skins" (Lk 5:37), that is, an old fleshly nature. When we accepted Jesus, we laid "aside [our] former way of life and the old self which deteriorates through illusion and desire, and [acquired] a fresh, spiritual way of thinking" (Eph 4:22-23). We "put on that new" skin, the new nature in Christ (Eph 4:24).
If you try to dabble in Christianity without radically changing your life, beware! The Holy Spirit will not only see right through you; He will "burst" right through you (see Lk 5:37). The abundant, new wine (Jn 2:7ff) of the Spirit "will spill out" (Lk 5:37) and you will lose what little spiritual life you thought you had (Mt 13:12). In fact, you will lose your taste for the things of God. You will say, " I find the old wine better" (Lk 5:39). That is to say, you will prefer your old lifestyle of sin to the life in the Spirit you tried to dabble in. The same principle applies to the new wine of Jesus' eucharistic cup. If you receive the new wine of the Eucharist unworthily, that is, with old skin, you may be drinking a judgment on yourself (1 Cor 11:29) and might even be bringing illness upon yourself (1 Cor 11:30).
Jesus' plan is not to just add a little flavor and richness to the old wine; rather, His new wine is so rich and explosive that our old skins can't begin to contain it (Mk 2:22). His plan is good; it is for our welfare, not for our destruction (Jer 29:11). Receive your new skin today! Receive the rich new wine of life in the Spirit.