Wherein God, willing more abundantly to shew unto the heirs of promise the immutability of his counsel, confirmed it by an oath:

Wherein God, being minded to show more abundantly unto the heirs of the promise the immutability of his counsel, interposed with an oath;

Wherein God, meaning more abundantly to shew to the heirs of the promise the immutability of his counsel, interposed an oath:

Wherein God, willing to shew more abundantly to the heirs of the promise the unchangeableness of his purpose, intervened by an oath,

Wherein God, being minded to shew more abundantly unto the heirs of the promise the immutability of his counsel, interposed with an oath:

in which God, more abundantly willing to shew to the heirs of the promise the immutability of his counsel, did interpose by an oath,

In the same way, since it was God's desire to display more convincingly to the heirs of the promise how unchangeable His purpose was,

So that when it was God's desire to make it specially clear to those who by his word were to have the heritage, that his purpose was fixed, he made it more certain with an oath;

In this matter, God, wanting to reveal more thoroughly the immutability of his counsel to the heirs of the promise, interposed an oath,

And therefore God, in his desire to show, with unmistakable plainness, to those who were to enter on the enjoyment of what he had promised, the unchangeableness of his purpose, bound himself with an oath.

In quo Deus volens uberius ostendere haeridibus promissionis immutabilem consilii sui firmitudinem, interposuit jusjurandum;

God, willing, etc. See how kindly God as a gracious Father accommodates himself to our slowness to believe; as he sees that we rest not on his simple word, that he might more fully impress it on our hearts he adds an oath. Hence also it appears how much it concerns us to know that there is such a certainty respecting his goodwill towards us, that there is no longer any occasion for wavering or for trembling. For when God forbids his name to be taken in vain or on a slight occasion, and denounces the severest vengeance on all who rashly abuse it, when he commands reverence to be rendered to his majesty, he thus teaches us that he holds his name in the highest esteem and honor. The certainty of salvation is then a necessary thing; for he who forbids to swear without reason has been pleased to swear for the sake of rendering it certain. And we may hence also conclude what great account he makes of our salvation; for in order to secure it, he not only pardons our unbelief, but giving up as it were his own right, and yielding to us far more than what we could claim, he kindly provides a remedy for it. Unto the heirs of promise, etc. He seems especially to point out the Jews; for though the heirship came at length to the Gentiles, yet the former were the first lawful heirs, and the latter, being aliens, were made the second heirs, and that beyond the right of nature. So Peter, addressing the Jews in his first sermon, says, "To you and to your children is the promise made, and to those who are afar of, whom the Lord shall call." (Acts 2:39.) He left indeed a place for adventitious heirs, but he sets the Jews in the first rank, according to what he also says in the third chapter, "Ye are the children of the fathers and of the covenant," etc. (Acts 3:25.) So also in this place the Apostle, in order to make the Jews more ready to receive the covenant, shows that it was for their sakes chiefly it was confirmed by an oath. At the same time this declaration belongs at this day to us also, for we have entered into the place quitted by them through unbelief Observe that what is testified to us in the Gospel is called the counsel of God, that no one may doubt but that this truth proceeds from the very inmost thoughts of God. Believers ought therefore to be fully persuaded that whenever they hear the voice of the Gospel, the secret counsel of God, which lay hid in him, is proclaimed to them, and that hence is made known to them what he has decreed respecting our salvation before the creation of the world.

Wherein God - On account of which; or since an oath had this effect, God was willing to appeal to it in order to assure his people of salvation.
Willing more abundantly - In the most abundant manner, or to make the case as sure as possible. It does not mean more abundantly than in the case of Abraham, but that he was willing to give the most ample assurance possible. Coverdale renders it correctly, "very abundantly."
The heirs of promise - The heirs to whom the promise of life pertained; that is, all who were interested in the promises made to Abraham - thus embracing the heirs of salvation now.
The immutability of his counsel - His fixed purpose. He meant to show in the most solemn manner that his purpose would not change. The plans of God never change; and all the hope which we can have of heaven is founded on the fact that his purpose is immutable. If he changed his plans; if he was controlled by caprice; if he willed one thing today and another thing tomorrow, who could confide in him, or who would have any hope of heaven? No one would know what to expect; and no one could put confidence in him. The farmer plows and sows because he believes that the laws of nature are settled and fixed; the mariner ventures into unknown seas because the needle points in one direction; we plant an apple tree because we believe it will produce apples, a peach because it will produce peaches, a pear because it will produce a pear. But suppose there were no settled laws, that all was governed by caprice; who would know what to plant? Who then would plant anything? So in religion. If there were nothing fixed and settled, who would know what to do? If God should change his plans by caprice, and save one man by faith today and condemn another for the same faith tomorrow; or if he should pardon a man today and withdraw the pardon tomorrow, what security could we have of salvation? How grateful, therefore, should we be that God has an "immutable counsel," and that this is confirmed by a solemn oath! No one could honor a God that had not such an immutability of purpose; and all the hope which man can have of heaven is in the fact that He is unchanging.
Confirmed it by an oath - Margin, "Interposed himself." Tyndale and Coverdale, "added an oath." The Greek is, "interposed with an oath" - ἐμεσιτεύσεν ὅρκῳ emesiteusen horkō. The word used here - μεσιτεύω mesiteuō - means to mediate or intercede for one; and then to intervene or interpose. The meaning here is, "that he interposed an oath" between himself and the other party by way of a confirmation or pledge.

The heirs of promise - All the believing posterity of Abraham, and the nations of the earth or Gentiles in general.
The immutability of his counsel - His unchangeable purpose, to call the Gentiles to salvation by Jesus Christ; to justify every penitent by faith; to accept faith in Christ for justification in place of personal righteousness; and finally to bring every persevering believer, whether Jew or Gentile, to eternal glory.

Wherein God, willing more (f) abundantly to shew unto the heirs of promise the immutability of his counsel, confirmed [it] by an oath:
(f) More than was needed, were it not for the wickedness of men who do not believe God, even though he swears.

Wherein God, willing,.... Or "wherefore", as the Syriac and Ethiopic versions render it; that is, whereas an oath is used among men to confirm anything that might be doubted; therefore God, in condescension to the weakness of men, made use of one; being very desirous and determined,
more abundantly to show unto the heirs of promise the immutability of his counsel; by which is meant, not the Gospel nor the ordinances of it, though these are sometimes called the counsel of God; but the decree of God, concerning the salvation of his people by Jesus Christ, which is immutable; as appears from the unchangeableness of his nature, the sovereignty of his will, the unsearchableness of his wisdom, the omnipotence of his arm, and the unconditionality of the thing decreed, and from that and the purpose of it being in Christ: and the immutability of this, God was willing to show "more abundantly" than in other purposes, though all God's purposes are unchangeable; or than had been shown to the Old Testament saints; and more than was necessary, had it not been for man's weakness: even to "the heirs of promise"; not any earthly temporal promise, but the promise of grace and glory; the promise of eternal life; the heirs of which are not only Abraham, Isaac, and Jacob, or God's elect among the Jews, but all that are Christ's; who are justified by his righteousness, believe in him, and are the children of God; for as many as are such are heirs of eternal glory, and of the promise of it: and that the unchangeableness of God's purpose in saving them by Christ might be manifest to them, and be out of all doubt, he "confirmed it by an oath"; his counsel and purpose; he not only determined in his mind that he would save them, and promised it in his covenant; but he also, to confirm it the more to the persons concerned in it, if possible, annexed his oath to it; or "he interposed or acted the part of a Mediator by an oath"; which some refer to Christ's mediation between God and Abraham, when he swore unto him, as before observed; but rather it expresses the interposition of the oath between God's purpose and promise, and man's weakness: God did as it were bind himself by his oath, or lay himself under obligation, or become a surety, for the fulfilment of his purpose and promise; which shows the super-abounding grace of God, the weakness of man, and what reason the heirs of promise have to believe.

Wherein--that is, Which being the case among men, God, in accommodation to their manner of confirming covenants, superadded to His sure word His oath: the "TWO immutable things" (Hebrews 6:18).
willing . . . counsel--Greek, "willing . . . will"; words akin. Expressing the utmost benignity [BENGEL].
more abundantly--than had He not sworn. His word would have been amply enough; but, to make assurance doubly sure, He "interposed with an oath" (so the Greek). Literally, He acted as Mediator, coming between Himself and us; as if He were less, while He swears, than Himself by whom He swears (for the less among men usually swear by the greater). Dost thou not yet believe, thou that hearest the promise? [BENGEL].
heirs of promise--not only Abraham's literal, but also his spiritual, seed (Galatians 3:29).

God interposed by an oath - Amazing condescension! He who is greatest of all acts as if he were a middle person; as if while he swears, he were less than himself, by whom he swears! Thou that hearest the promise, dost thou not yet believe?