Symbolism, Imagery, Allegory
For most people, flesh is just the pudgy stuff between your skin and bones. Sometimes you wish you had a little less of it.
The early Christians, though? They didn't want any of it.
No, this wasn't just a really crazy fad diet. It was a way of staying totally centered on God.
Flesh and Blood
Paul talks over and over about "the flesh." He means two things. Sometimes he's just talking about the physical body. Head, shoulders, knees, and toes—that good stuff. Like when he says that he'll probably "remain in the flesh" (Philippians 1:24) for the sake of the Philippians. In other words, he's not gonna die. That's good news.
But most of the time, Paul uses the word "flesh" to mean the opposite of the Holy Spirit.
• "Having started with the Spirit, are you now ending with the flesh?" (Galatians 3:3)
• "For what the flesh desires is opposed to the Spirit, and what the Spirit desires is opposed to the flesh; for these are opposed to each other, to prevent you from doing what you want." (Galatians 5:17)
• "If you sow to your own flesh, you will reap corruption from the flesh; but if you sow to the Spirit, you will reap eternal life from the Spirit." (Galatians 6:8)
• "For it is we who are the circumcision, who worship in the Spirit of God and boast in Christ Jesus and have no confidence in the flesh." (Philippians 3:3)
Here, the flesh isn't just your body; it's your whole state of mind. People are who living in the flesh are not focused on God. They're worried about everything that's going on in their little world. They only care about what's happening to them here and now, not what God wants for them.
So, to sum up: flesh focus = bad. Spirit focus = good. We love it when things work out so neatly.
Bodies Are Bad
But not everyone has seen it this way. Some folks read the whole flesh-is-bad thing as one big diss toward the human body. This has led to an interesting body and soul dynamic in a lot of popular Christian thought. Basically, the idea is that our bodies don't matter—our souls are the most important thing. When we die, we'll leave behind our bodies and our souls will go to Heaven…where we'll all fit in size 4 jeans.
Really, this isn't what Paul's saying at all. In fact, he specifically tells us that our bodies do matter. Why else would we he supply us with a whole laundry list of things not to do with our bodies?
The works of the flesh are obvious: fornication, impurity, licentiousness, idolatry, sorcery, enmities, strife, jealousy, anger, quarrels, dissensions, factions, envy, drunkenness, carousing, and things like these. I am warning you, as I warned you before: those who do such things will not inherit the kingdom of God. (Galatians 5:19-21)
So yeah, bodies are important. And according to Paul, if you're using yours to have sex, start fights, or get drunk, there's gonna be trouble.