Charles Ellicott Commentary Exodus 7:15

"Get thee unto Pharaoh in the morning; lo, he goeth out unto the water; and thou shalt stand by the river`s brink to meet him; and the rod which was turned to a serpent shalt thou take in thy hand." — Exodus 7:15 (ASV)

He goes out to the water. —Perhaps to bathe, like the princess who saved Moses (Exodus 2:5), perhaps to inaugurate some festival in the river’s honor. Of these the Egyptian calendar contained several.

The river’s brink. —Hebrew, the lip of the river. .