17. Abraham fell on his face and rejoiced. He said in his heart, "Can there be a child to a man who is a hundred years old, and can Sarah bear a child at ninety!"

REJOICED. Onkelos and Saadiah replace Scripture's "laughed." This is to protect Abraham's dignity and to show that he had trust in the divine message. The targumist does not deviate in translating Sarah's reaction in 18:12 because tradition, as well as the bible itself, indicates that she had no trust that she would give birth to a son in her old age; her laughter suggest that she ridiculed the idea. With regards to Abraham, Rashi, Radak, and Nachmanides understand the text as our targumist, but Neophyti, Pseudo-Jonathan, the Fragmented Targums, and ibn Ezra replace it with the more delicate "wondered." According to these sources, while Abraham trusted that the prediction would occur, he thought how unusual it would be for an elderly couple to bear a son. Another explanation for the targumic deviation is based on verse 19, where God tells Abraham to name his son Yitzchak (Isaac), a name based on the Hebrew root tzachak, "laughed." The translator may have reasoned that God would not instruct Abraham to use this name for his child if it would be a reminder of Abraham's improper reaction. As such, vayitzchak in our passage must be describing a proper - and not an improper - reaction, and "rejoiced" its intended meaning.

A HUNDRED YEARS OLD. Abraham's surprise is not based on the fact that he was a hundred years old, since as long as a man retains his capacity to produce semen he can have children, and we see that he had many children with Keturah forty years later (25:2). He wondered how Sarah, who was ninety, could have a child (Nachmanides).

Excerpted with permission from Onkelos on the Torah by Israel Drazin and Stanley M. Wagner, published by Gefen Publishing Company.