"I am the Vine, and you are the branches"--Romans 8:3-6

3 For what the law could not do in that it was weak through the flesh, God did by sending His own Son in the likeness of sinful flesh, on account of sin: He condemned sin in the flesh, 4 that the righteous requirement of the law might be fulfilled in us who do not walk according to the flesh but according to the Spirit. 5 For those who live according to the flesh set their minds on the things of the flesh, but those who live according to the Spirit, the things of the Spirit.6 For to be carnally minded is death, but to be spiritually minded is life and peace.

I like plant metaphors!
To have the life of the Spirit is, I think, another way of putting the same truth that’s expressed by saying you’re part of the Body of Christ or you are a branch on the vine. The sap that runs through you belongs to a larger organism than yourself, a complete function of itself, of which you aren’t the whole but to which you wholly belong. That function or direction of the larger organism is to be completely your function; ie, if you are a leaf on a plant you are entirely given over to producing photosynthetic material, to the greater end that the plant might flourish and produce fruit. Such is the law of the plant—what happens to a living leaf, just by the nature of the way things are. To the extent that you’re not doing this, you’re not acting like part of the plant and you’re in enmity to it—you’re a parasite and a disease. And if the sap isn’t in you, you’re not part of the plant and as far as the plant is concerned you are dead.. You might still perform actions suitable to not being part of the plant, such as cell breakdown and getting eaten by bugs, but you’re not part of the greater life anymore. And you’re really pathetic, and you’ll die really soon. Such is the law of decomposition—the way nature works on a detached leaf. I think John 15 is talking about this. In this way, the law that brings death is actually the same law that brings life.

But that’s a passive metaphor… you’re part of the plant, its sap circulates through you, etc. What I like so much about Romans 8 (or maybe it’s just this translation) is its combination of active and passive words. When you’re in the Spirit, you are “walking” according to the Spirit, and you “set your mind” on the things of the Spirit. That’s what bothered me about this passage; because it makes it seem like once you are, through Christ Jesus, filled with the life of the Spirit, you will automatically be transformed into a creature that is free from the ways of the flesh and doesn’t follow them anymore. This doesn’t go along with observation, either of myself or of other people. It’s way too easy to sometimes have your mind on the things of the spirit and on the things of the flesh.

Martin Luther says that Romans 8 “gives comfort to those who are engaged in this warfare (struggling against the flesh, I think), and says that the flesh shall not condemn them.” That is, that as long as they are struggling against it and towards God, in Christ Jesus they are pleasing to him even as they fail and fail. We are children of God as long as we strive to put the flesh to death. So my plant metaphor breaks down a bit here. Not really, though. Life is just a very long wait to see if a graft will take or fail, assuming that the severed branch has some choice in the matter of whether it will be transformed to the new parent plant or remain itself.