Speak unto the children of Israel. God still recognized Moses as mediator between Himself and His people.
Every one of them. Not as individuals, but as representatives of each tribe.
Twelve rods. These were the official symbols of the tribal authority vested in the princes. The reference is not to rods or sticks freshly cuts from trees. The same Hebrew word is used of the staff of Judah (Gen. 38:18) and of the rod of Moses (Ex. 4:2). There were 12 tribes in addition to Levi; but there was also a rod for Aaron. Commentators disagree as to whether Joseph was counted as one tribe, or separately as Ephraim and Manasseh, or whether Aaron’s rod was in addition to the 12 for the tribal princes.
Write thou. Compare Eze. 37:16. The writing may have been done with some form of ink, or was perhaps cut in. The names of the princes, one for each rod, were placed on the staves.