12. The birth of Isaac 21:1-21

God proved faithful to His promise by providing Isaac. Abraham and Sarah responded with obedience and praise. Ishmael, however, became a threat to Abraham's heir and consequently his father sent him away into the wilderness where God continued to provide for him and his mother.

 God's provision and Abraham and Sarah's response 21:1-7

The emphasis in this brief section is on the faithfulness and power of God in keeping His promise and providing an heir miraculously through Sarah (17:16; 18:14). Note the threefold repetition of "as He had said,""as He had promised,"and "of which God had spoken"(vv. 1-2). The tension of anticipation finally subsides, but only temporarily.

God "visited"Sarah (v. 1, NIV). The Hebrew word translated "visited"(paqad) also appears when God intervened to save the Israelites from Egyptian bondage (50:24-25; Exod. 4:31) and when He ended a famine (Ruth 1:6). It also occurs when He made Hannah conceive (1 Sam. 2:21) and when He brought the Jewish exiles home from Babylonian captivity (Jer. 29:10). Thus its presence here highlights the major significance of Isaac's birth.

Abraham's obedience in naming his son "Isaac"(17:19) and circumcising him on the eighth day (17:12) was an expression of worship.

Isaac's name ("laughter") was appropriate for two reasons.

1. Isaac would be a source of joy to his parents as the fulfillment of God's promised seed.

2. Both Abraham and Sarah had laughed in amazement and unbelief respectively when told that God had chosen to bless them by giving them a son so late in life (17:17; 18:12).⁵⁵⁹

 The expulsion of Ishmael and God's care of him and Hagar 21:8-21

All was not well in Abraham's household. Ishmael was a potential rival to Isaac's inheritance. This section records another crisis in the story of Abraham's heir.

Normally the son of a concubine became the heir of his mother but not of his father (cf. Judg. 9:1-3). Now that Abraham had a son by his wife, Sarah did not want Ishmael to share Isaac's inheritance. The Hebrew word translated "mocking"(v. 9) comes from the same root as Isaac's name and means "laughing."However this participle is in the intensive form indicating that Ishmael was not simply laughing but ridiculing Isaac (cf. Gal. 4:29). Abraham understandably felt distressed by this situation since he loved Ishmael as well as Isaac (cf. 17:18). God appeared to him again (the seventh revelation) to assure Abraham that Sarah's desire was in harmony with His will (cf. 17:19-21). He encouraged Abraham to divorce Hagar.

"But how could God ask Abraham to do evil if divorce is always a sin? The answer must be that divorce in this case is either not a sin or else is the lesser of two evils."⁵⁶⁰

"The key to Sarah's demand lies in a clause in the laws of Lipit-Ishtar where it is stipulated that the father may grant freedom to the slave woman and the children she has borne him, in which case they forfeit their share of the paternal property."⁵⁶¹

The focus of this revelation is a clarification of God's purposes for each of the two sons. God would bless Abraham through Ishmael as well as through Isaac.

"As Cain suffered both banishment from the divine and protection by the divine, so Ishmael is both loser and winner, cut off from what should be his but promised a significant lineage."⁵⁶²

The concluding description of Ishmael's experiences (vv. 14-21) provides information essential to understanding and appreciating later references to him and his descendants in the text. Ishmael became the father of 12 sons (25:13-16) as Jacob did. From his sons came the Arab nations that have ever since been the chief antagonists of the Israelites.⁵⁶³Hagar chose a wife for her son from her homeland, Egypt.

"In this respect she does not display the wisdom used by Abraham in choosing, as he did, a god-fearing wife for his son."⁵⁶⁴

God not only makes promises but also provision. His provision of what He has promised results in great joy and should lead to separation from whatever might hinder His program of blessing.⁵⁶⁵