And Moses told Aaron means that he informed him or reported to him. All the words of the LORD means, as Good News Translation expresses it, “everything that the LORD had said.” But this is qualified with the relative clause with which he had sent him, which may be understood in one of two ways: either a) “everything the LORD had said when he commissioned him” (Translator’s Old Testament), or b) “everything … the LORD had sent him to say” (New English Bible). Good News Translation follows the interpretation of a), rendering the clause as “when he told him to return to Egypt.” This, of course, is a direct reference to Moses’ commissioning at the burning bush. Translators may choose either of these two interpretations. If b) is followed, another way to express this is “Moses told Aaron everything that the LORD had sent him to Egypt to say” or “… had told him to say in Egypt.”

And all the signs refers to the three “miracles” (Good News Translation) that the LORD had charged him to do, namely, changing his rod into a snake, his hand into a diseased hand, and water from the Nile river into blood. Here the word for signs (ʾothoth) is the same as in verses 8-9, but not the same as that used in verse 21. (See the comment on “wonders” at 3.20.) The word for charged him in this last clause means “ordered him” (Good News Translation). Revised Standard Version and others add the words to do or “to perform.”

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 .