Went to Pharaoh is literally “they entered toward Pharaoh,” so this second encounter was probably inside the palace. Did as the LORD had commanded refers to the instructions given in verse 9. It must be assumed that the king demanded a miracle from them, as verse 9 anticipates. And Aaron cast down his rod probably at Moses’ command. Cast down … before means “threw … down in front of.”

His servants were probably important men who served as attendants and as advisors to the king. They should be thought of as “his officers” (Good News Translation), “his officials” (New International Version, New Jerusalem Bible), or “his courtiers” (New English Bible, New Jewish Publication Society’s Tanakh). It became a serpent means “it turned into a snake” (using the same word as in verse 9).

Quoted with permission from Osborn, Noel D. and Hatton, Howard A. A Handbook on Exodus. (UBS Helps for Translators). New York: UBS, 1999. For this and other handbooks for translators see here .