(20) The mention of the word "mediator" implies a contract to which there are at least two parties. But where there is a contract there must be also conditions, and if these conditions are not observed the whole falls to the ground. Such was the Law. The Law was not kept, and therefore the blessings annexed to it were forfeited. On the other hand, the promise depends upon God alone. He gave it, and He will assuredly keep it, no matter what man may do. God alone is concerned in it.

This passage is a conspicuous instance of the advance which has been made in New Testament exegesis. It is said to have received as many as 250 or 300 (according to another estimate, even 430) interpretations, but at the present moment there is a tendency to acquiesce in that given above, which, it is hoped, will be thought satisfactory.

Now a mediator is not a mediator of one.--The very idea of a mediator involves two parties at least. The Law had a mediator, therefore the Law involves two parties. In other words, it is a contract.

But God is one.--On the other hand, God, the giver of the promise, stands alone: therefore the promise is not a contract; and, resting on God, it is indefeasible.

Verse 20. - This verse, closing the short paragraph commencing the verse which precedes it, appears designed to mark the difference of the relations which subsisted between the Lord and Israel at the time of the giving of the Law, compared with those which subsist between God and Abraham's seed in the covenant of grace. Now a mediator is not a mediator of one (ὁ δὲ μεσίτης ἑνὸς οὐκ ἔστιν). The article with μεσίτης, literally, "the mediator," marks the noun as a class noun, giving it the sense, "a mediator as such." Compare the use of the article in τοῦ ἀποστόλου, in "the signs of an apostle" (2 Corinthians 12:12); in ὁ ἀγαθὸς ἄνθρωπος, "a good man" (Matthew 12:25); in ὁ ἐργάτης, "the labourer is worthy of his hire" (Luke 10:7). The clause means this: a mediator implies the existence of more than one party, of two parties at least, for him to mediate between; of two parties not at one, but standing on such terms towards each other as make his intervention necessary. So far as it characterized the giving of the Law viewed in contrast with the establishment of the covenant of grace, the mediation of Moses, as has been already observed, did not put an end to the estrangement between the Lord and Israel: the estrangement went on throughout Moses' life; throughout, the Israelites stand marked with the brand of "transgression." The genitive ἑνός, "of one," is the same as the genitive in μεσίτης Θεοῦ καὶ ἀνθρώπων, literally, "Mediator of God and men," in 1 Timothy 2:5: it marks the party or parties towards whom the function of mediation is exercised; so that what the apostle here affirms is that there cannot be only one such party. But God is one (ὁ δὲ Θεὸς εῖς ἔστιν). When we consider the number of interpretations given of this clause in connection with the preceding, which have literally been computed by hundreds (the reader will find a spieilegium of some sixty or eighty of them in Meyer), we may infer with certainty that the sense which the apostle intended to convey is not an obvious one - not one which lies near the surface. So much appears, however, in the highest degree probable, that he refers either to some disadvantageous circumstance attaching to the Law or to some advantageous circumstance attaching to the covenant of promise, and is viewing the two in contrast the one with the other. On these grounds the present writer has long since acquiesced in the view propounded by Windischmann in his Commentary on this Epistle, and which is accepted by Bishop Ellicott, that the unity here predicated of God is the oneness subsisting between the Father and the Son. God is one in the Father and in his Son - Christ our Lord. The fact is now present to the apostle's mind, and is presently after stated by him (Galatians 4:4), that the Son has been "sent forth" by God to redeem us and make us sons, and has thus become the "Christ," that "Seed of Abraham" to which the promises had been made (ver. 29 of this chapter). Hereby the most perfect oneness is established between God and the heirs of the promise; for these are "clothed with Christ" (ver. 27) the Son of God; and he being one with the Father, they in and through him are really and permanently "reconciled into God," as the apostle writes in Colossians 1:20. Compare our Lord's words in his intercessory prayer (John 17:21, 23), "That they all may be one; even as thou, Father, art in me, and I in thee, that they also may be in us. I in them, and thou in me; that they may be perfected into one." That this sense lies deep down in the apostle's words and would not have readily been presented by them to the minds of his readers, forms no valid objection to this interpretation; for the history of the exegesis of the passage proves that this must have been the case with the sense which the apostle really designed to indicate, whatever that was. On the other hand, it is a sense which perfectly suits the requirement of the context; for it illustrates the superiority of the covenant of the promise to the covenant of the Law in the strongest manner possible. The nut has a very hard shell, but it yields a delicious kernel.

3:19-22 If that promise was enough for salvation, wherefore then serveth the law? The Israelites, though chosen to be God's peculiar people, were sinners as well as others. The law was not intended to discover a way of justification, different from that made known by the promise, but to lead men to see their need of the promise, by showing the sinfulness of sin, and to point to Christ, through whom alone they could be pardoned and justified. The promise was given by God himself; the law was given by the ministry of angels, and the hand of a mediator, even Moses. Hence the law could not be designed to set aside the promise. A mediator, as the very term signifies, is a friend that comes between two parties, and is not to act merely with and for one of them. The great design of the law was, that the promise by faith of Jesus Christ, might be given to those that believe; that, being convinced of their guilt, and the insufficiency of the law to effect a righteousness for them, they might be persuaded to believe on Christ, and so obtain the benefit of the promise. And it is not possible that the holy, just, and good law of God, the standard of duty to all, should be contrary to the gospel of Christ. It tends every way to promote it.Now a mediator is not a mediator of one,.... A mediator supposes two parties he stands between, and these at a distance from, or disagreeing with each other; where there is but one party, there can be no need of, nor any reason for, a mediator; so Christ is the Mediator between God and men, the daysman, Job 9:33, that lays his hands upon them both; and Moses, he was the mediator between God and the Israelites:

but God is one; not in person, for there are three persons in the Godhead, the Father, the Word, and the Holy Ghost, and these three are one, in nature and essence; so that though there are three persons, there is but one God, and who is the God both of Jews and Gentiles; who is of one mind concerning them, and has taken them into one and the same covenant, and makes use of one and the same method in the justification of them: but the true sense of the phrase here is, that whereas a mediator supposes two parties at variance, "God is one of the two"; as the Ethiopic version reads the words; he is a party offended, that stands off, and at a distance, which the law given by angels in the hand of a mediator shows; so that that is rather a sign of disagreement and alienation, and consequently that justification is not to be expected by it.