Paul starts this verse with for, which connects it with verse 16. We will not satisfy the desires of the human nature, if we live by the Spirit, because of the fact that human nature and the Holy Spirit are at enmity with each other.

The word translated human nature is “flesh,” and is to be taken in the same sense as in the previous verse. Here flesh and the Spirit are pictured as opposing each other. The contrast between the desires of the human nature and of the Spirit of God may be expressed in some languages as “For what we as human beings want is against what God’s Spirit wants, and what God’s Spirit wants is against what we as human beings want.” There may, however, be difficulties involved in some languages since a verb such as “want” may require a goal. Therefore, one may need to translate “For what we as human beings want to do is against what the Spirit of God wants us to do, and what the Spirit of God wants us to do is against what we as human beings want to do.”

After expressing the conflict, Paul comes up with another statement: These two are enemies, and this means that you cannot do what you want to do.

There are different ways of interpreting these two are enemies. One is to regard this statement as simply a summary of the first part of the verse. On the other hand, the first part of the verse can be taken as a general statement of the conflict, and the second part as a statement of the conflict in the experience of the individual believer. In both cases, the last clause you cannot do what you want to do is interpreted as expressing result. Further, it is neutral, referring to both good and evil desires. What Paul would mean, then, is that since the Spirit and the flesh are in conflict within the believer, this results in the believer’s loss of his freedom.

These two are enemies may be translated as either “What we want to do and what God’s Spirit wants us to do are opposed,” or “We as human beings and God’s Spirit are enemies of one another,” or “… opposed to one another.”

However, a third interpretation of these two are enemies is possible. That is to take you cannot do what you want to do to refer to doing what the flesh wants, which would take Paul’s meaning to be that since the Spirit opposes the flesh, then the believer is not free to do what he wants to do, insofar as following the flesh is concerned. The last part of this verse would then read: “These two are enemies, and this means that if the Spirit directs your lives, you cannot do what you want to do, which is to satisfy the desires of the human nature.”

The merit of this last interpretation is that it connects this verse more closely with both what precedes and what follows.

Quoted with permission from Arichea, Daniel C. and Nida, Eugene A. A Handbook on Paul’s Letter to the Galatians. (UBS Handbook Series). New York: UBS, 1976. For this and other handbooks for translators see here .