Sforno on Exodus 19:24/ספורנו על שמות י״ט:כ״ד

1לך רד, now, when I am speaking with you, be with them at the bottom of the mountain.

2ועלית אתה ואהרן, at the conclusion of the Ten Commandments and the portion Mishpatim as we read in Exodus 24,1. The Torah writes there: עלה אל ה' אתה ואהרן “ascend to G’d, you and Aaron.” [the elders and Aaron there are bidden to prostrate themselves from a distance. Ed.]