Literally, this is “but the mediator is not of one, but God is one.” The phrase “of one” most probably refers to the parties in a given transaction. Paul is therefore saying that unless there are two parties, a mediator is not needed (compare Jerusalem Bible “now there can only be an intermediary between two parties”; New American Bible “there can be no mediator when only one person is involved”; New English Bible “an intermediary is not needed for one party acting alone”). Rather than the negative form a go-between is not needed when only one person is involved, it is often better to use a positive statement, for example, “a go-between is only needed when there are two parties,” or “… two persons involved.” The implication is that a go-between is required when two parties have different interests in a particular solution, and therefore some compromise position needs to be worked out.

The theological implications of the verse are difficult to understand. Here Paul again uses rabbinical methods to drive home his point. His point here is the superiority of the promise over the Law. What he has in mind all along is that the promise was not given through a go-between, but came directly from God. It is really difficult to make sense of the final statement in this verse, God is one. It reflects an Old Testament declaration, but its application to this particular context is certainly not clear. In some languages one cannot say literally “God is one.” It is, of course, possible to say “God is one God,” but this would appear to be repetitious and meaningless. Apparently the thought behind the expression employed by Paul is that “God acted directly,” or “God acted as one person without a go-between,” and in some instances this may be the only legitimate way to communicate the intent of this rather obscure expression.

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 .