Charles Ellicott Commentary Genesis 18:14

"Is anything too hard for Jehovah? At the set time I will return unto thee, when the season cometh round, and Sarah shall have a son." — Genesis 18:14 (ASV)

Is anything too hard for the Lord? —Hebrew, Is anything too wonderful for Jehovah? At last it is made evident that the travelers are messengers from God; but until this declaration, there could have been, at most, only a dim feeling that the visitation was more than human. Though the angel does not claim for himself divinity, yet the narrator prefixes to his words, And Jehovah said. In some ineffable way there was an identity between Jehovah and the angel.