The relation of this statement to its context is not clear, a fact reflected in the more than 250 different explanations that commentators and others have given it. The context precludes considering it a restatement of
Deut. 6:4,
“The Lord our God is one Lord,” and suggests that Paul here refers back to the covenant promise mentioned in
Gal. 3:18. The entire chapter deals with the difference between salvation by faith in the covenant promise and salvation by the
“works of the law.” The
“but” in
v. 20 implies a contrast between the law of
vs. 19 and 20, and the covenant promise of
v. 18. The covenant promise was not
“added” to anything; it was delivered by God Himself. Accordingly,
v. 20 might be paraphrased as follows:
“Now a mediator implies an agreement between two parties, but the covenant promise was unilateral—it was contingent upon God alone and thus required no mediator.” Whereas the old covenant (see on
Eze. 16:60) was in the form of a contract between God and the chosen people, mediated by Moses (see
Ex. 19:3-8; 20:19-21; 21:1; 24:3-8; see on
Gal. 3:15, 19), the new, or everlasting, covenant vouchsafed by God to Abraham was simply in the form of a promise. With the old covenant there was an agreement on the part of the people to obey, whereas with the new covenant it is necessary only to accept the promise by faith, and obedience follows naturally (
Gen. 26:5).