And the LORD said to Moses begins a new paragraph, but a more natural transitional word like “Again” (Good News Translation) should be used. When you go back to Egypt may be understood in context as “Now that you are going back to Egypt” (Good News Translation), since verse 20 indicates that Moses had already “set out” (Good News Translation).

See introduces a clause that literally says “See all the wonders that I placed in your hands and you will do them before Pharaoh.” It is probably to be understood as a command to see that you do, or “be sure to perform” (Good News Translation). But some interpret it as a command to “keep in mind” (New English Bible) or “be prepared to perform” (Jerusalem Bible). New Jerusalem Bible renders the clause as an exclamation, “Think of the wonders I have given you power to perform, once you are back in Egypt!” Good News Translation‘s interpretation is the more likely one. Before Pharaoh may also be rendered as “in the sight of Pharaoh [or, the king],” or even “before the face of the king.” Other ways to express see that you do are “set your heart to perform” or “don’t fail to perform.” The word for miracles (mofethim) is not the same as the word for “signs” (ʾothoth) in the earlier verses of this chapter. (See the comment on “wonders” at 3.20.) Which I have put in your power, literally “in your hands,” means “which I have given you the power to do.”

But I will harden his heart uses an expression found many times in Exodus to describe the stubbornness of the Pharaoh. Sometimes it is the LORD who hardens the king’s heart; sometimes he hardens his own heart. The heart was thought to be the center of thinking, of intelligence, and a hard heart indicated a stubborn attitude. In each instance one of three different Hebrew words is used to describe his heart as either “difficult,” “strong,” or “heavy,” but the meaning is always that the king is “stubborn.” In this verse the word meaning “strong” is used. In many languages there will be similar figurative expressions for “stubbornness,” using the “heart,” “liver,” or “stomach.”

So that introduces a purpose clause (Revised Standard Version), while “and” seems to introduce a result clause (Good News Translation). Either interpretation is possible, since the common Hebrew conjunction waw must often be translated according to the context. The result is still that the king will not let the people go; it is a matter of interpretation whether this is also the LORD’s purpose in hardening his heart. People in the phrase not let the people go may also be rendered as “the people of Israel” or “the Israelites.”

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 .