Cyril of Alexandria, on Gen 17:17

“Abraham fell upon his face, and laughed, saying in his heart: Shall a son, thinkest thou, be born to him that is a hundred years old? and shall Sara that is ninety years old bring forth?”

“He was not laughing because he did not believe, as some might imagine, but rejoicing because he did. "He laughed" is sometimes put in place of "he rejoiced," as it is also in the Gospels. And for this reason, he also "fell on his face" and marveled in his heart.”

Imported from an open dataset — not yet checked against the printed edition.