Peter Pett's Commentary on the Bible
Numbers 17:1-3
Yahweh Commands Each Tribe to Lay a Rod Before Him in the Tent of Testimony One For Each Head of Their Father's House (Numbers 17:1)
‘And Yahweh spoke to Moses, saying,'
Again it is emphasised here that we have the words of Yahweh as spoken to Moses.
‘Speak to the children of Israel, and take of them rods, one for each fathers' house, of all their princes according to their fathers' houses, twelve rods. You write every man's name on his rod.'
All the men of Israel were to be involved in this. It is possible that Levi were included among ‘the twelve' and that Manasseh and Ephraim were for this event treated as one tribe, the rods representing the ‘households' of the original patriarchal fathers. But a rod was taken for each of their fathers' houses, and the names of each of the chieftains of those fathers' houses was written on the rods. This would suggest in the light of previous references to twelve chieftains that the ‘twelve' rods were in contrast with Aaron's rod. (Alternately one rod may have represented Joseph, including both Ephraim and Manasseh. It was Joseph who was to be ‘a fruitful bough' (Genesis 49:22), but not as pertaining to the priesthood).
The word for ‘rods' also indicates ‘tribes, and can in fact be used to indicate either. Thus the rods symbolised each tribe.
‘And you shall write Aaron's name on the rod of Levi, for there shall be one rod for each head of their fathers' houses.'
On the rod of Levi the name of Aaron was to be written. There was to be one for each head of their fathers' houses. In the light of the earlier divisions in Chapter s 1-4 we are probably therefore to see that there were thirteen rods, the twelve which represented Israel in contrast with the Levites, and the one that specifically represented Aaron.
Here Aaron is depicted as the head of the house of Levi. That may well be why earlier he was called ‘the Levite' as the head of the family (Exodus 4:14).