Rashi on Exodus 18:12/רש"י על שמות י״ח:י״ב

1עלה — Translate this according to its usual meaning: a burnt-offering, which was burnt entire and completely.

2וזבחים AND SACRIFICES — i. e. peace-offerings.

3ויבא אהרן וגו׳ AND AARON CAME, etc. — But where had Moses gone? Was it not he who had gone out to meet him and had been the cause of all the honour shown to him? But the explanation why he is not mentioned as having come to eat bread with Jethro is that he was standing by and waiting upon them (Mekhilta).

4לפני האלהים BEFORE GOD — From this statement that they were “before God” we may learn that one who takes part in (more lit., who has enjoyment from) a meal at which scholars sit may be regarded as though he has enjoyment from the splendour of the Shechina (Berakhot 64a; cf. Mekhilta).