In Genesis chapter twenty-one, verse one, Isaac, the son of promise, was born to Abraham and Sarah. Through Isaac, God would continue His covenant with Abraham. Twenty-five years had passed before God’s promise to Abraham was fulfilled.
Sarah conceived and had a son for Abraham at the set time for it to occur according to God. The arrival of Isaac is troubled by the existence of Abraham’s oldest son Ishmael who was in his early teens. The clouded issue is how Sarah reacts with anger and hurt feelings towards Ishmael and his mother, Hagar. Before this incident, Sarah is partly responsible for Ishmael’s place in the family. When she was barren, Sarai, her name before now, told Abraham to go with her handmaiden and have a child.
Now Isaac is born, Sarah cannot tolerate having Ishmael and Hagar around. She would have reason to be concerned, on one level, that Ishmael would somehow take Isaac’s place as Abraham’s heir. Then on a feast day, Abraham celebrated Isaac for being weaned, and Sarah saw Ishmael mocking. Maybe he was playing with baby Isaac as a teen, getting acquainted with his half-brother, and she might have caught a glimpse and interpreted it the wrong way.
Today, situations like these occur in the life of families. Prior relationships with others between spouses or relatives coming to live together under the same roof from other related families will experience some form of tension. Assuredly, different lifestyles that others are unaccustomed to could disturb the other members. Attitudes and ways of conduct may vary, but understand that we grew up differently.
Eventually, Ishmael and Hagar had to leave and go on their own because it was not getting better with Sarah towards them. God knew they had to leave Abraham. Nevertheless, God did not forsake Hagar and Ishmael, for they were under the presence and care. God had a purpose for Ishmael that parallels his plan for Isaac, namely, that He would “make him a great nation.”