We have been set free from the Law, Paul has said, but set free so that we might we might now live as we should, serving one another in love. But how? By the Spirit. Earlier Paul wrote “After beginning by means of the Spirit, are you now trying to finish by means of the flesh?” (3:3); here Paul explains what it means and looks like to go on by means of the Spirit. We are still absolutely in the realm of grace, but it is not effortless and purely passive on our part, there is to be determined and active cooperation. Life in the Spirit is marked by a real fight and real change.
Christian experience is one of inner conflict, caused by the ongoing insistent pull of the flesh and the new opposing desires of the Spirit. Naturally, what we want is to gratify the desires of our sinful nature, to please ourselves, but the Spirit gives us a new desire to please God. If we were still under the Law, such an unremitting battle, with inevitable defeats along the way, would be a cause for despair, but if we are led by the Spirit then we are not under Law (v.18) but under grace, so our standing with God is not determined by our obedience and we need not feel condemned with every failure. Nor is the outcome of this battle in doubt: the sinful nature remains, but we are under the rule of the Spirit and, led by Him, we “will not gratify the desires of the flesh” (v.16). There will be change; there will be fruit.
When the flesh is in the driving seat it will inevitably pull us into actions and attitudes that are clearly ugly and destructive. The list that follows in verses 19-21 is not exhaustive, but obvious examples of what gratifying the desires of the flesh leads to. The first three speak of how sex becomes corrupted in illicit, unnatural or uncontrolled abuse. “Idolatry and witchcraft” speak of the corruption of true worship – worshipping what is not God, and seeking to manipulate spiritual powers to satisfy my own needs. Then (“hatred … envy”) Paul speaks of how relationships are corrupted and destroyed, as much by our wrong attitudes as our actions. “Drunkenness and orgies” speak of a lack of self-control and restraint. The warning in v.21b is a serious one. Reading the list, all of us will be aware how we have sinned, but the sense of “those who live like this” is of a habitual pattern of life. To live like this indicates we are not being led by the Spirit and therefore have no share in the kingdom of God. In so far as any of the things in this list are habitual problems for us, then this is a warning we need to heed, determining to live by the Spirit, for only in His strength can the power of sin be broken.
And living by the Spirit there will be change – unmistakeable fruit, as beautiful as the acts of the flesh are ugly. Paul speaks of “fruit” (singular), not “fruits” (plural), suggesting this is a rounded picture of the character the Spirit produces in us, all of a piece, we can’t pick and choose. It is of course the character of Christ himself, for the Spirit of Christ seeks to produce His character in us, and it is perfectly in tune with the Law (cf. 5:14).
Such fruit is the Spirit’s work in us (a work we must expect to be gradual, not instantaneous, and, whilst the flesh remains, partial), but we are not passive, as the final verses show. Verse 24 speaks of a past event, when we turned to Christ in repentance and were united to him in his death (as in 2:20), but it has ramifications for the present. We must keep remembering the significance of our conversion, remembering that sin is no longer our master, that we belong now to Christ Jesus. Constantly, verse 25 urges us, we are to seek to “keep in step with the Spirit”, attuning ourselves to His desires and His will, and seeking to follow His lead. And special attention should be given (v.26) to our relationships within the church: as vv.13-15 insisted too, life in the Spirit is especially seen in our life together (as Paul will go on to further elaborate in chapter 6).