Tafsiran Bilangan 34:22: Chizkuni

ולמטה בני דן נשיא, “and of the tribe of Dan, a prince;” the reason that the word: “prince” has not been mentioned with the first three tribes listed here, is because we knew already that Calev of the tribe of Yehudah, as the only survivor of his tribe that had been an adult at the Exodus would be the leader after Nachshon had died. He had already been called by G-d Himself as “My servant.” (Numbers 14,24) As far as the tribe of Binyamin is concerned, we know that Eldod, a colleague of Meydod, both from this tribe had been elevated to the status of prophets. According to another interpretation, seeing that at a later stage involving the concubine a Givah, (Judges chapter 20) he would be dishonorably involved, he is not here referred to as a prince. The same consideration applies to the tribe of Shimon, whose prince in short order will be involved in the shameful episode with the Midianite woman Cosbi, Moses did not bestow the title prince upon him posthumously. Rashi had pointed out already in his commentary on Parshat Balak, that the people of the tribe of Shimon had treated Zimri as their leader. (Numbers 25,6) There had been no need for a leader of the tribes of Reuven and Gad to be appointed, as these tribes had already received their ancestral heritage on the east bank of the Jordan. There seems to be no logical order to the listing of the tribes here. It does not follow the birth-order of the tribal ancestor, nor the order in which the tribes marched for forty years in the desert, nor the birth-order of the tribal mothers.