But Moses’ hands grew weary is literally “And the hands of Moses [were] heavy,” which means, as Good News Translation translates, that “Moses’ arms grew tired.” So they took a stone refers to Aaron and Hur, and these names should be advanced from their present position in the verse. The stone here is smaller than the large rock or boulder mentioned in verse 6, but it was large enough to sit on. And put it under him suggests that they moved it to where Moses had been standing. And he sat upon it indicates that the stone was the proper size for sitting. These three short clauses may be combined: “Aaron and Hur brought a stone for him to sit on” (Good News Translation).

And Aaron and Hur should be changed to “they” if these names are advanced to they took a stone. Held up his hands is literally “they took hold of his hands.” This really means “they supported his hands” (New Jewish Publication Society’s Tanakh, New American Bible), or better “his arms” (Good News Translation). One on one side, and the other on the other side is literally “one from this and one from that.” Translator’s Old Testament makes it quite clear: “Then, standing on either side of him, they each held up one of his hands.”

So his hands were steady, literally “and it was [that] his hands were firmness,” means “holding them steady” (Good News Translation), or “supported his arms in the same position” (Contemporary English Version). Translator’s Old Testament has “In this way his hands remained firmly raised.” Until the going down of the sun is quite literal. It is more natural to say “until the sun went down” (Good News Translation), or “until the sun set” (New Revised Standard Version).

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 .