Genesis 17:15

17:15 Then God said to Abraham, “As for your wife, you must no longer call her Sarai; ¹  Sarah ²  will be her name.

Genesis 17:17

17:17 Then Abraham bowed down with his face to the ground and laughed ³  as he said to himself, ⁴  “Can ⁵  a son be born to a man who is a hundred years old? ⁶  Can Sarah ⁷  bear a child at the age of ninety?” ⁸ 

[17:15]  ¹ tn Heb “[As for] Sarai your wife, you must not call her name Sarai, for Sarah [will be] her name.”

[17:15]  ² sn Sarah. The name change seems to be a dialectical variation, both spellings meaning “princess” or “queen.” Like the name Abram, the name Sarai symbolized the past. The new name Sarah, like the name Abraham, would be a reminder of what God intended to do for Sarah in the future.

[17:17]  ³ sn Laughed. The Hebrew verb used here provides the basis for the naming of Isaac: “And he laughed” is וַיִּצְחָק (vayyitskhaq); the name “Isaac” is יִצְחָק (yitskhaq), “he laughs.” Abraham’s (and Sarah’s, see 18:12) laughter signals disbelief, but when the boy is born, the laughter signals surprise and joy.

[17:17]  ⁴ tn Heb “And he fell on his face and laughed and said in his heart.”

[17:17]  ⁵ tn The imperfect verbal form here carries a potential nuance, as it expresses the disbelief of Abraham.

[17:17]  ⁶ tn Heb “to the son of a hundred years.”

[17:17]  ⁷ sn It is important to note that even though Abraham staggers at the announcement of the birth of a son, finding it almost too incredible, he nonetheless calls his wife Sarah, the new name given to remind him of the promise of God (v. 15).

[17:17]  ⁸ tn Heb “the daughter of ninety years.”