Long awaited son is born! verses 1-7
At Jehovah's appointed time, the child promised to Abraham and Sarah is born! How happy they are! Abraham calls him Isaac. It is interesting that Issac means "laughter". Remember how Abraham had laughed for joy, concerning Isaac, while Sarah had laughed incredulously.
Being part of Abraham's household, we know that Isaac was circumcised at eight weeks and taught since infancy about God.
Isaac grows and is protected verses 8-13
Some years later, the day Isaac is weaned arrives, and Abraham prepares a big feast in celebration. During the feast Sarah notices Ishmael, "poking fun" at his younger half brother, Isaac. This proved to be more serious than teasing a younger brother. The Hebrew word tsa-chaq' translated, "poking fun", can have an offensive connotation. Cooks Commentary says, "It probably means ...mocking laughter." Now, Ishmael laughs concerning Isaac, but in derision, probably in a persecuting and tyrannical spirit. In fact, the apostle Paul writes the mistreatment of Isaac by Ishmael is affliction, yes persecution. (Compare: Galatians 4:29)
This poking of fun was no innocent child's play on the part of Ishmael (he was 14 years older than Isaac.) Notice verse 10, "So she (Sarah) began to say to Abraham: "Drive out this slave girl and her son, for the son of this slave girl is not going to be an heir with my son, with Isaac." From this verse we can see Ishmael taunted Isaac over heirship.
Abraham is not happy about sending his son Ishmael away, however, Jehovah told Abraham to listen to his wife, in this instance, as it was to be Isaac, not Ishmael that will be called Abraham's seed. Jehovah reassures Abraham that Ishmael would not be forgotten, as one of Abraham's offspring, he would become a nation.
Ishmael and Hagar sent away. verses 14-21
If Ishmael and Hagar had accepted Jehovah's choice regarding the promised seed, coming through Isaac and submitted to Jehovah's arrangement, not stirring up contention, they could have lived a peaceful life under Abraham's roof. However, Ishmael's demonstration of scorn toward Isaac led to the dismissal of him and his mother from Abraham's household. Abraham gave them provision for their journey. He "took bread and a skin water bottle and gave it to Hagar, setting it upon her shoulder, and the child, and then dismissed her." Hagar appears to have lost her way in the wilderness, and when the water ran out and Ishmael became exhausted, "she threw the child under one of the bushes." (v. 14, 15) Ishmael, was about 19 years of age. Hagar's act of 'throwing ' the child down implies she was evidently supporting her tired son. She must have withdrew her support suddenly.
The name Ishmael, means "God heard", and Jehovah indeed did hear his cry for help. Jehovah provided the necessary water, and allowed him to live to become an archer. As a nomadic inhabitant of the Paran Wilderness, he fulfilled the prophecy that said of him: "He will become a zebra of a man, His hand will be against everyone, and the hand of everyone will be against him; and before the face of all his brothers he will tabernacle." (compare: Genesis 16:12) Hagar found an Egyptian wife for her son.
Living peaceably as an alien resident. Verses 22-34
The Philistine king Abimelech reminds Abraham of his alien status, and that he resides in the land of Philistia by Abimelech's consent, he requests Abraham to swear an oath of faithful conduct.
Some of the Philistines seized a well in this area by violence, seemingly unknown to Abimelech. He and his chief of his army approach Abraham to propose a covenant of peace. Abraham is not happy about the act of violence in seizing the well, and severely criticized Abimelech. Abimelech avows his ignorance, and concludes a covenant with Abraham accepting seven female lambs from him in evidence of Abraham's title to the well. So we see, both Abraham & Abimelech have taken an oath for peace. Abraham and his household continue living in peace serving their God Jehovah.