God was telling Abraham these things. Abraham could have heard a voice from a cloud or from the air or in his inner ear. Or he could have been in a tent and heard the voice. Whatever the method, Abraham’s audible response was, “O that Ishmael might live!” What does this account tell us about Abraham? He was 99 years old (verse 24). The promise was originally made when he was 75—24 years earlier. He had first thought that his chief servant, Eliezer, would be the heir, but God said the seed would come out of Abraham’s loins. Then he and Sarah thought that perhaps the seed was to come through Abraham but not through Sarah, so 13 years earlier (verse 25) he conceived Ishmael through Hagar the concubine. Abraham’s comment here in verse 18 indicates that he was resigned to Ishmael’s being the seed. He was saying, “I will be satisfied if Ishmael is the seed.” Abraham was not pressing the matter but was simply expressing a spirit of resignation and submission. Subconsciously, too, he was probably thinking of Sarah’s age. It would be a greater miracle for Sarah to bear a child now than for him to sire one, for he had fathered Ishmael when 86 years old. However, Abraham probably felt he, too, could no longer have children; that is, he probably became impotent after having Ishmael. And Sarah was definitely barren. Therefore, the miracle with Abraham and Sarah was twofold. (Many men over 100 had children both before and after Abraham, so impotency seemed to be his situation.)
