Galatians 3:20

ὁ δὲ μεσίτης, “but a mediator.” The article is generic, or, perhaps better, recalls the mediator just mentioned: cf. Galatians 3:23; Galatians 3:25.

δέ, adversative, probably to the thought that a mediator is in itself good, or possibly to the Jewish glorification of Moses as mediator.

ἑνὸς οὐκ ἔστιν, i.e. does not belong to the category of “one.” In a promise God acts alone; when a mediator is employed in any act of His there is an implication of plurality and separation from Himself so long as the thing mediated is in force.

ὁ δὲ θεὸς εἷς ἐστίν. But God is essentially one in His nature and character. The idea of unity in word and act is most consonant with Him. St Paul would doubtless have written ἕν if this would not have suggested to his readers too material and impersonal a thought to be connected with God.

The verse thus serves to bring out the superiority of the Promise over the Law. It is in fuller agreement with God’s own character than was the Law. For the Promise was given directly by God to Abraham and his seed: the Law was given mediately, through Angels and by Moses. This mediation is a mark of inferiority set upon it.
The verse is so difficult that it is said to have received above 250 (Meyer) or 430 (Jowett) interpretations. The most important source of differences lies in the second half, many expositors explaining it as “God is one party and the Israelites are a second,” i.e. the Law depends for its fulfilment upon the ability of the second party to keep it, and is in this respect inferior to the unconditioned character of the Promise. But though at first sight the masculine εἷς suggests this interpretation, yet this is not so closely connected with the immediate context as that given above.

Observe (1) St Paul’s purpose in this verse is not to state, much less to prove, monotheism. He assumes this, and does not even mention it save in so far as it is included under the unity of God’s nature. (2) Galatians 3:19-20 are not opposed to the Christian doctrine of the mediatorship of Christ. St Paul would thoroughly agree with the ordinary Jewish view that a mediatorship in the sense of an intermediate being between God and man is unnecessary. Nay, he says here as much, for, though a believer in Christ, he speaks disparagingly of such a mediator. The fact is that to him, as to us, Christ is not distinct from God, but is God. When on the other hand he speaks of ἄνθρωπος Χριστὸς Ἰησοῦς as μεσίτης θεοῦ καὶ� (1 Timothy 2:5) he is regarding Him in His humanity, putting, for the moment, His Godhead out of sight. See the quotation from a letter by Archbishop Temple, Appendix, Note D.

NOTE D

Archbishop Temple on Galatians 3:20

“I prefer to take the argument in this sense. The law was ordained for a temporary purpose and showed its temporary character by being given through a Mediator. For God, being the eternal unity, can make no abiding covenant with any except those whom He so unites with Himself as to exclude the notion of a Mediator altogether. Or to put it in another way—a mediator implies separation, and a covenant made through a mediator implies perpetual separation while the covenant lasts. Such a covenant therefore cannot be eternal, for God the Eternal One cannot allow perpetual separation from Himself.” A letter in 1852 to the Rev. Robert Scott, afterwards Dean of Rochester (Life of Archbishop Temple, II. p. 494).