Genesis 17:21

But my covenant will I establish with Isaac, which Sarah shall bear unto thee at this set time in the next year.

EXPOSITORY (ENGLISH BIBLE)

Benson Commentary

Genesis 17:21. He names that child Isaac, that is, laughter, because Abraham rejoiced in spirit when this son was promised him.

Matthew Henry's Concise Commentary

17:15-22 Here is the promise made to Abraham of a son by Sarai, in whom the promise made to him should be fulfilled. The assurance of this promise was the change of Sarai's name into Sarah. Sarai signifies my princess, as if her honour were confined to one family only; Sarah signifies a princess. The more favours God confers upon us, the more low we should be in our own eyes. Abraham showed great joy; he laughed, it was a laughter of delight, not of distrust. Now it was that Abraham rejoiced to see Christ's day; now he saw it and was glad, Joh 8:56. Abraham, dreading lest Ishmael should be abandoned and forsaken of God, put up a petition on his behalf. God gives us leave in prayer to be particular in making known our requests. Whatever is our care and fear, should be spread before God in prayer. It is the duty of parents to pray for their children, and the great thing we should desire is, that they may be kept in covenant with Him, and may have grace to walk before him in uprightness. Common blessings are secured to Ishmael. Outward good things are often given to those children of godly parents who are born after the flesh, for their parents' sake. Covenant blessings are reserved for Isaac, and appropriated to him.

Barnes' Notes on the Bible

Abraham seems up to this time to have regarded Ishmael as the promised seed. Hence, a feeling of anxiety instantly penetrates his breast. It finds utterance in the prayer, "Oh that Ishmael might live before thee." He asks "life" for his beloved son - that is, a share in the divine favor; and that "before God" - that is, a life of holiness and communion with God. But God asseverates his purpose of giving him a son by Sarah. This son is to be called Isaac - he that laughs or he shall laugh, in reference to the various emotions of surprise and delight with which his parents regarded his birth. Abram's prayer for Ishmael, however, is not unanswered. He is to be fruitful, beget twelve princes, and become a great nation. But Isaac is to be the heir of promise. At the present season next year he is to be born. The communication being completed, "God went" up from Abram.

Jamieson-Fausset-Brown Bible Commentary

19, 20. The blessings of the covenant are reserved for Isaac, but common blessings were abundantly promised to Ishmael; and though the visible Church did not descend from his family, yet personally he might, and it is to be hoped did, enjoy its benefits.

Matthew Poole's Commentary

The covenant of the promised Seed to come out of his loins, and of life and salvation to accrue to himself and to his posterity by virtue of that Seed; in comparison whereof God speaks slightly of all the temporal blessings conferred upon Ishmael, though in themselves they were great and glorious. By which it may sufficiently appear that Abraham’s faith, whereby he is said to be justified, Romans 4:1-25, had a further reach in it than to his own immediate child, even to the Messias, whose day therefore Abraham is said to have seen, John 8:56.

Gill's Exposition of the Entire Bible

But my covenant will one establish with Isaac,.... The covenant of circumcision; for though Ishmael was circumcised, and his posterity practised that rite, yet it was not enjoined them of God; nor was it to them, or served the same purpose as to the Israelites; and particularly the promise of the land of Canaan, made in that covenant, belonged only to the posterity of Isaac, and to those only in the line of Jacob, and especially that of the Messiah springing from him, which circumcision had a respect unto:

whom Sarah shall bear unto thee, at this set time, in the next year: that is, at the end of nine months, which is the set time a woman goes with child.

Geneva Study Bible

But my covenant will I establish with Isaac, which Sarah shall bear unto thee at this set time in the next year.

EXEGETICAL (ORIGINAL LANGUAGES)

Pulpit Commentary

Verse 21. - But my covenant will I establish with Isaac, whom Sarah shall bear unto thee at this set time in the next year (cf. Genesis 21:2). Genesis 17:21

Keil and Delitzsch Biblical Commentary on the Old Testament

The appointment of the sign of the covenant was followed by this further revelation as to the promised seed, that Abram would receive it through his wife Sarai. In confirmation of this her exalted destiny, she was no longer to be called Sarai (שׂרי, probably from שׂרר with the termination ai, the princely), but שׂרה, the princess; for she was to become nations, the mother of kings of nations. Abraham then fell upon his face and laughed, saying in himself (i.e., thinking), "Shall a child be born to him that is a hundred years old, or shall Sarah, that is ninety years old, bear?" "The promise was so immensely great, that he sank in adoration to the ground, and so immensely paradoxical, that he could not help laughing" (Del.). "Not that he either ridiculed the promise of God, or treated it as a fable, or rejected it altogether; but, as often happens when things occur which are least expected, partly lifted up with joy, partly carried out of himself with wonder, he burst out into laughter" (Calvin). In this joyous amazement he said to God (Genesis 17:18), "O that Ishmael might live before Thee!" To regard these words, with Calvin and others, as intimating that he should be satisfied with the prosperity of Ishmael, as though he durst not hope for anything higher, is hardly sufficient. The prayer implies anxiety, lest Ishmael should have no part in the blessings of the covenant. God answers, "Yes (אבל imo), Sarah thy wife bears thee a son, and thou wilt call his name Isaac (according to the Greek form Ἰσαάκ, for the Hebrew יצחק, i.e., laughter, with reference to Abraham's laughing; Genesis 17:17, cf. Genesis 21:6), and I will establish My covenant with him," i.e., make him the recipient of the covenant grace. And the prayer for Ishmael God would also grant: He would make him very fruitful, so that he should beget twelve princes and become a great nation. But the covenant, God repeated (Genesis 17:21), should be established with Isaac, whom Sarah was to bear to him at that very time in the following year. - Since Ishmael therefore was excluded from participating in the covenant grace, which was ensured to Isaac alone; and yet Abraham was to become a multitude of nations, and that through Sarah, who was to become "nations" through the son she was to bear (Genesis 17:16); the "multitude of nations" could not include either the Ishmaelites or the tribes descended from the sons of Keturah (Genesis 25:2.), but the descendants of Isaac alone; and as one of Isaac's two sons received no part of the covenant promise, the descendants of Jacob alone. But the whole of the twelve sons of Jacob founded only the one nation of Israel, with which Jehovah established the covenant made with Abraham (Exodus 6 and 20-24), so that Abraham became through Israel the lineal father of one nation only. From this it necessarily follows, that the posterity of Abraham, which was to expand into a multitude of nations, extends beyond this one lineal posterity, and embraces the spiritual posterity also, i.e., all nations who are grafted ἐκ πίστεως Ἀβραάμ into the seed of Abraham (Romans 4:11-12, and Romans 4:16, Romans 4:17). Moreover, the fact that the seed of Abraham was not to be restricted to his lineal descendants, is evident from the fact, that circumcision as the covenant sign was not confined to them, but extended to all the inmates of his house, so that these strangers were received into the fellowship of the covenant, and reckoned as part of the promised seed. Now, if the whole land of Canaan was promised to this posterity, which was to increase into a multitude of nations (Genesis 17:8), it is perfectly evident, from what has just been said, that the sum and substance of the promise was not exhausted by the gift of the land, whose boundaries are described in Genesis 15:18-21, as a possession to the nation of Israel, but that the extension of the idea of the lineal posterity, "Israel after the flesh," to the spiritual posterity, "Israel after the spirit," requires the expansion of the idea and extent of the earthly Canaan to the full extent of the spiritual Canaan, whose boundaries reach as widely as the multitude of nations having Abraham as father; and, therefore, that in reality Abraham received the promise "that he should be the heir of the world" (Romans 4:13).

(Note: What stands out clearly in this promise-viz., the fact that the expressions "seed of Abraham" (people of Israel) and "land of Canaan" are not exhausted in the physical Israel and earthly Canaan, but are to be understood spiritually, Israel and Canaan acquiring the typical significance of the people of God and land of the Lord - is still further expanded by the prophets, and most distinctly expressed in the New Testament by Christ and the apostles. This scriptural and spiritual interpretation of the Old Testament is entirely overlooked by those who, like Auberlen, restrict all the promises of God and the prophetic proclamations of salvation to the physical Israel, and reduce the application of them to the "Israel after the spirit," i.e., to believing Christendom, to a mere accommodation.)

And what is true of the seed of Abraham and the land of Canaan must also hold good of the covenant and the covenant sign. Eternal duration was promised only to the covenant established by God with the seed of Abraham, which was to grow into a multitude of nations, but not to the covenant institution which God established in connection with the lineal posterity of Abraham, the twelve tribes of Israel. Everything in this institution which was of a local and limited character, and only befitted the physical Israel and the earthly Canaan, existed only so long as was necessary for the seed of Abraham to expand into a multitude of nations. So again it was only in its essence that circumcision could be a sign of the eternal covenant. Circumcision, whether it passed from Abraham to other nations, or sprang up among other nations independently of Abraham and his descendants (see my Archologie, 63, 1), was based upon the religious view, that the sin and moral impurity which the fall of Adam had introduced into the nature of man had concentrated itself in the sexual organs, because it is in sexual life that it generally manifests itself with peculiar force; and, consequently, that for the sanctification of life, a purification or sanctification of the organ of generation, by which life is propagated, is especially required. In this way circumcision in the flesh became a symbol of the circumcision, i.e., the purification, of the heart (Deuteronomy 10:16; Deuteronomy 30:6, cf. Leviticus 26:41; Jeremiah 4:4; Jeremiah 9:25; Ezekiel 44:7), and a covenant sign to those who received it, inasmuch as they were received into the fellowship of the holy nation (Exodus 19:6), and required to sanctify their lives, in other words, to fulfil all that the covenant demanded. It was to be performed on every boy on the eighth day after its birth, not because the child, like its mother, remains so long in a state of impurity, but because, as the analogous rule with regard to the fitness of young animals for sacrifice would lead us to conclude, this was regarded as the first day of independent existence (Leviticus 22:27; Exodus 22:29; see my Archologie, 63).