Moses is the one to reply to Pharaoh, and Aaron does not seem to be involved. Be pleased to command me is literally “glorify yourself over me” and has been understood in different ways. (Note the variety in recent translations.) It is best to interpret this as a statement of respect on Moses’ part, but spoken with a bit of irony (New International Version “I leave to you the honor of setting the time”). This will emphasize even more the superior power of Moses’ God over that of the Pharaoh and his magicians. For it means that the king, by commanding when Moses should pray, will indirectly be calling on a God he has so far refused to recognize. Good News Translation‘s “I will be glad to pray for you” seems to have missed this irony. Contemporary English Version is better: “All right,” Moses answered, “You choose the time when….”
When I am to entreat probably refers to “the time when I am to pray” (Good News Translation) rather than to the time when the frogs are to be destroyed. The meaning seems to be that Moses will wait until the designated time, and then when he prays the frogs will be destroyed. However, some translations make a distinction here, suggesting that Moses will pray immediately, asking the LORD to destroy the frogs at the time chosen by the Pharaoh (so Jerusalem Bible, New Jewish Publication Society’s Tanakh, and Childs). Although this is a possible interpretation, translators are encouraged to follow Good News Translation. For you and for your servants and for your people means that Moses is willing to “intercede” (New English Bible) for all the Egyptians—the king, his “officers,” and all his “subjects” (New American Bible, New Jerusalem Bible).
When I am to entreat … that the frogs be destroyed is ambiguous in the Hebrew. Literally it says “when I will pray for you … to destroy the frogs.” Verse 8 makes it clear, of course, that Moses will pray to Yahweh. This may mean either that Moses will ask the LORD to destroy the frogs on behalf of the king and his people, or that he will pray for the king and his people, and then the LORD will destroy the frogs. Good News Translation seems to favor this second meaning, but the first meaning is to be preferred, along with most translations. In many languages it will be necessary to make it explicit that Yahweh is the one who will destroy the frogs. Translator’s Old Testament provides a good model: “I will pray to the LORD on your behalf … and ask him to destroy the frogs.”
From you and your houses uses the singular pronoun, but it may be necessary to translate you and your into the plural. There is no intention to exclude the servants or the people. And be left only in the Nile means that not all the frogs will be destroyed; there will still be frogs as before, but they will stay only in the river. One may express this as “Then you will be rid of the frogs from all your houses; there will be none left except those in the Nile River.”
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 .