Rashi on Exodus 6:26/רש"י על שמות ו׳:כ״ו

1הוא אהרן ומשה THESE ARE THAT AARON AND MOSES who are mentioned above where it states (v. 20) that Jochebed bore them to Amram. הוא אהרן ומשה There are some passages where Scripture mentions Aaron before Moses (as here) and other passages where it mentions Moses before Aaron; this is done in order to indicate that they were equal in all respects (more lit., that they weighed alike) (Mekhilta).

2על צבאתם — This is the same as בצבאותם with their hosts — all their hosts according to their tribes. Sometimes the word על is merely used in place of a single letter (ב as a prefix); e. g., (Genesis 27:40) “על חרבך shalt thou live” which is the same as בחרבך, by thy sword; (Ezekiel 33:26) “Ye stand על חרבכם” which is the same as בחרבכם, by your sword.