15 God said to Abraham, "As for Sarai your wife, you shall not call her name Sarai, but her name will be Sarah.
*Minor differences ignored. Grouped by changes, with first version listed as example.
As for Sarai thy wife God now promises to Abraham a legitimate seed by Sarai. She had been (as I have said) too precipitate, when she substituted, without any command from God, her handmaid in her own place. Abraham also bad been too pliant in following his wife, who foolishly and rashly wished to anticipate the design of God; nevertheless, their united fault did not prevent God from making it known to them that he was about to give them that seed, from the expectation of which, they had, in a manner, cut themselves off. Whence the gratuitous kindness of God shines the more clearly, because, although men impede the course of it by obstacles of their own, it nevertheless comes to them. Moreover, God changes the name of Sarai, in order that he may extend her preeminence far and wide, which in her former name had been more restricted. For the letter y (yod) has the force among the Hebrews of the possessive pronoun: this being now taken away, God designs that Sarah should every where, and without exception, be celebrated as a sovereign and princess. [1] And this is expressed in the context, when God promises that he will give her a son, from whom at length nations and kings should be born. And although at first sight this benediction appears most ample, it is still far richer than it seems to be, in the words here used, as we shall see in a little time.
1 - Sarah shall her name be. Heb., srh, Sarah. Sarai properly signifies "my princess," as if sustaining that relation to a single individual or to a family. The restriction implied in the possessive "my" is now to be done away: her limited pre-eminence is to be unspeakably enlarged. Thus, instead of "my princess," she is henceforth to bear an appellation importing "princess of a multitude," and corresponding with the magnificent promise made to her, ver. 16. -- Bush, Notes on Genesis
Thou shalt not call her name Sarai, but Sarah - See note on Genesis 17:5.
And God said unto Abraham,.... After he had changed his name, and given him the covenant of circumcision:
as for Sarai thy wife, thou shalt not call her name Sarai, but Sarah her name shall be; her former name Sarai signifies "my princess", or rather "princesses", being to him in the room of many, and better than ten thousand; yet only a princess to him, and in his family, being sole mistress there: but Sarah signifies, as Jarchi observes, "princess" absolutely, because she was princess over all the princes and people that should come of her, as well as be the mother and princess of all female believers, who are called her daughters, 1-Peter 3:6.
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, John 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.
As for Sarai . . . I will . . . give thee a son also of her--God's purposes are gradually made known. A son had been long ago promised to Abraham. Now, at length, for the first time he is informed that it was to be a child of Sarai.
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 (Ex 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).
Sarah shall her name be - The same letter is added to her name that was to Abraham's. Sarai signifies my princess, as if her honour were confined to one family only: Sarah signifies a princess, viz. of multitudes.
*More commentary available at chapter level.