(15) Sarai.--Probably princely, an adjective of the same form as shaddai, Genesis 17:1; while Sarah means princess. The change of name shows that she was admitted to the covenant. (Comp. Genesis 17:10.)

Verse 15. - And God said unto Abraham, As for Sarai thy wife, - who, not having hitherto been mentioned in any of the promises, is now expressly taken into covenant, and accordingly receives a new name (cf. Ver. 5; Genesis 32:28; Revelation 3:12) - thou shalt not call her name Sarai, - "my princess" (Gesenius); "princely, noble" (Ikenins, Rosenmüller, Keil, Delitzsch); "the heroine" (Knobel); "strife, contention" (Ewald, Murphy), with special reference to her struggle against sterility. (Kalisch) - but Sarah "princess" (Gesenius), the meaning being that, whereas formerly she was Abram's princess only, she was henceforth to be recognized as a princess generally, i.e. as the mother of the Church (Jerome, Augustine), or as princess to the Lord, the letter A being taken from the name Jehovah, as in the change of Abram into Abraham (the Rabbis); though Ikenius and Rosenmüller derive from an Arabic root, sara, to have a numerous progeny - shall her name be.

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.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.