Matthew Poole and continuators on Numbers 21:18

18 The princes digged the well, the nobles of the people digged it, by the direction of the lawgiver , with their staves . And from the wilderness they went to Mattanah:

Either by themselves, or by others whom they commanded to do it.

Or, with the lawgiver, i. e. Moses, they together with Moses, or they by Moses his direction, and appointment, which is signified ver. 16.

Which are here mentioned, either 1. as the ensigns of their authority, Iudg. 5. 14. by which they gave this command of digging: or 2. as the instruments of their work, not that they did formally and effectually dig the Well or receptacle for the water, for which spades were more proper than staves, but that as Moses smote the rock with his rod, so they struck the earth with their staves making onely some small impression, onely for form sake or as a sign that God would cause the water to flow forth out of the earth where they smote it, as he did before out of the rock.