Or, as the place is fitly rendered by others, because of the word, or matter of, or about the frogs which he had given or propounded to Pharaoh. Because he had given his word both for the thing and the time of it, he prayed more earnestly lest God should be dishonoured, and Pharaoh have occasion of triumph. The Hebrew verbs to put and to give are frequently exchanged, as appears by comparing 1 Kings 10:9, with 2 Chronicles 9:8; and Isaiah 42:1, with Matthew 12:18. Moses cried unto the Lord: though he was assured that the frogs would depart at his word, yet he would use the means appointed by God for the accomplishment of it.
Related Commentaries of Exodus 8:12
Exodus 8:12
12 And Moses and Aaron went out from Pharaoh: and Moses cried unto the LORD because of the frogs which he had brought against Pharaoh.