Exodus 8:9

And Moses said unto Pharaoh, Glory over me, be magnified above me, an expression used by Moses to refer all honor to Jehovah; when shall I intreat for thee, and for thy servants, and for thy people, to destroy, literally to cut off, to put away definitely, the frogs from thee and thy houses, that they may remain in the river only? The fact that Pharaoh was even permitted to set the time for the deliverance from the plague was to direct his thoughts to the superior power of the God of the Hebrews.