Charles Ellicott Commentary Exodus 8:9

"And Moses said unto Pharaoh, Have thou this glory over me: against what time shall I entreat for thee, and for thy servants, and for thy people, that the frogs be destroyed from thee and thy houses, and remain in the river only?" — Exodus 8:9 (ASV)

And Moses said ... Glory over me. —This phrase seems equivalent to—“I submit to your will,” “I am content to do your bidding.” It was probably an ordinary expression of courtesy in Egypt on the part of an inferior to a superior; but it was not a Hebrew idiom, and so does not occur elsewhere.

When shall I entreat?—Rather, as in the margin, against when? or for when?—that is, what date shall I name in my prayer to God for when the plague shall be removed? And so, in the next verse, for “to-morrow” translate against to-morrow. It seems strange that Pharaoh did not say, “To-day, this very instant;” but perhaps he thought even Jehovah could not do so great a thing at once.