Rashi on Numbers 21:18/רש"י על במדבר כ״א:י״ח

1באר חפרוה THE WELL, [PRINCES] DIGGED IT means: This is the well which the princes, Moses and Aaron, digged (cf. Targum Jonathan on).

2במשענתם means WITH THE STAFF.

3וממדבר מתנה AND FROM THE WILDERNESS was it given them [as a מתנה, a gift].