Once upon a time, there was a man who had been promised by God that his children would outnumber the sands of the sea and the stars in the sky. But he and his wife despaired as time and time again, his wife was unable to bear a child. They prayed and waited patiently, but still there was no hope. Eventually, his wife even gave her husband her handmaid as a concubine and surrogate, to perform what her body would not do.
Imagine the depths of her joy and self-recrimination when that handmaid succeeded in bearing a son almost immediately.
Imagine her pain when, long after once-beautiful Sarah was too old to have any more children, a perfect stranger wandered up to their home and told her husband she would bear a son.
Imagine her joy and consternation when it turned out he was right.
Her son, Isaac, was a miracle child. Not only was he born to a mother who had long since given up all hope of having a child, he was the fulfillment of prophecy. Through him, all the promises of the Lord were finally possible. He proved that God's promises would never be forgotten.