And the LORD came down means that Yahweh actually descended from a higher place. The And should probably not be translated as “Then,” since that would suggest that Yahweh was speaking with Moses before he descended to the mountain. Upon Mount Sinai, to the top of the mountain seems repetitive, so Good News Translation has “The LORD came down on the top of Mount Sinai.” (Similar is New International Version.) Some translations treat this as a temporal clause (New Revised Standard Version, New American Bible), beginning with “When the LORD descended….” This will be a natural translation in many languages.

And the LORD called Moses to the top of the mountain is also wordy, repeating both the LORD and Moses. Again Good News Translation combines the two clauses into one, “and called Moses to the top of the mountain.” Contemporary English Version has “and told Moses to meet him there.” In certain languages this will be direct speech; for example, “The LORD called to Moses, ‘Come up here.’ ” The sharp contrast between down and up in these verses should be retained because of its symbolic and theological meaning.

Alternative translation models for this verse are:

• The LORD [or, Yahweh] came down to the top of Mount Sinai and told Moses to meet him there. Moses went up.

• … and called to Moses, “Come up here.” Moses went to the top of the mountain to meet with Yahweh.

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 .