This verse explains the purpose of verse 1. The channel of communication will be from God to the Pharaoh through Moses and Aaron. You shall speak means that Moses is to speak to Aaron, that is, he will “tell Aaron” what to say. All that I command you means that God will give specific commands to Moses, and then Moses in turn will “repeat” (New Jewish Publication Society’s Tanakh) them to Aaron. And Aaron … shall tell Pharaoh completes the chain of communication.

In the Hebrew to let the people of Israel go is literally “and he will let go the sons of Israel.” Because of the “and,” a few translations interpret this as the result of the negotiations with the king, not as what Aaron is to say to him. New English Bible, for example, has “… he will tell Pharaoh, and Pharaoh will let the Israelites go….” Similarly Translator’s Old Testament has “Then Pharaoh will let the Israelites leave his land.” But this interpretation ignores what is said in both the preceding and the following verses. Most translations therefore interpret it as a summary of all the commands that will be communicated to the Pharaoh through Moses and Aaron.

Pharaoh is a title for “the king” of Egypt. The people of Israel were “the Israelites,” and go out of his land means “leave his country,” that is, Egypt.

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 .