By the time of this story Abraham had been following the Lord for many years. He had enjoyed the Lord's appearing on quite a number of occasions. He had grown close to the Lord to the extent that when the Lord was about to judge Sodom He confided with Abraham what he was about to do. This gave Abraham the opportunity to intercede on behalf of the righteous there. The Lord answered Abraham's prayer and rescued Lot.

But even though Abraham had progressed that far in following the Lord, he still had a hidden weakness. The weakness was exposed when he drifted away from the place where he had enjoyed the Lord's appearing. Right away he lost his boldness and became timid and fearful. He was even afraid to say that Sarah was his wife because he thought that someone might kill him to get her. Neither of them said anything when the Philistine king took Sarah to be a member of his harem.

The Lord's speaking to the king in a dream was not just to protect Sarah. That speaking also exposed Abraham's weakness and failure. Abraham had to take the king's rebuke and then pray that the Lord would heal the Philistine women so that they could bear children. Abraham had been praying that his wife could bear a son for many years without receiving the answer to his prayer. Now he had to pray the same prayer for others. This forced Abraham to put himself aside. So the whole experience: Abraham's failure, the Lord's protection, the king's rebuke, and his needing to pray for others instead of himself; was one of the ways the Lord used to teach Abraham to trust in Him rather than relying on his own schemes.

Eventually the Lord did answer Abraham's prayer and gave him a son as an heir. Abraham and Sarah had hoped and prayed for a son for many years. About the time when they would have been ready to give up any hope the Lord promised that they would have a son. But even after that nothing happened for another long period of time. Isaac was not born until Abraham was a hundred years old and Sarah was ninety years old. By then they were sure that they would never have any children. Their faith had been exhausted until the Lord revived and strengthened it through His visitations.

Both God and Abraham desired an heir who would continue the line of faith that Abraham was pioneering. Eventually, at the time God chose, Isaac was born to be such an heir. Abraham would naturally have preferred that the Lord answer his prayer much sooner. But there were some real advantages to the Lord's timing. First of all, if Abraham had received the answer he was looking for the first time he prayed, he would not have needed to pray about it any more. Instead there was a long time between his first prayer and the Lord's answer. During that time he both made some mistakes and had a number of experiences of the Lord's appearing. The result was that he knew both himself and the Lord much better than before.

Another advantage to the Lord's timing was that when Isaac finally was born, both Abraham and Sarah were clear that his birth was the Lord's doing. Earlier on Abraham might have thought that he himself could produce what the Lord wanted. Once he considered that could no longer do anything at all, then the Lord did what only He could do.