Or HaChaim on Numbers 34:19/אור החיים על במדבר ל״ד:י״ט

1 למטה יהודה, for the tribe of Yehudah. We need to explore why the leaders of the tribes of Yehudah, Shimon, and Benjamin are not given the title נשיא in our paragraph. Perhaps the reason is connected to the fact that the names of these three tribes appear quite close to the words ונשיא אחד נשיא אחד in verse 18 so that the Torah saw no need to repeat the word נשיא again. Starting with verse 22 the names of the tribes are so far removed from verse 18 that the Torah saw fit to add the title נשיא when mentioning the leader of the respective tribes.

2I have a seen a comment in the name of Rabbenu Nissim that there was no need to write the word נשיא in connection with the tribe of Yehudah as everybody knew that it was Calev ben Yefuneh. In the case of the tribe of Shimon the reason was that this tribe was not worthy of having a leader with the title נשיא in view of the affair with Zimri. In the case of the tribe of Benjamin, there was no need to mention that Eldod held the title נשיא, as he held a better title having been a prophet already since the time the 70 elders had been chosen in Numbers 11,16-29. Calling Eldod a "prince" would have amounted to a demotion rather than a promotion for him.

3Perhaps one may add that the term נשיא was not allocated to the temporary leader of the tribe of Yehudah seeing that this tribe would produce a king for the entire nation, not just a prince for itself. A similar consideration may have applied to the tribe of Benjamin seeing that the realisation of a Jewish Kingdom, i.e. the first king of Israel, Saul, would come from that tribe. As far as the absence of a mention of a prince for the tribe of Shimon is concerned, the reason advanced was quite adequate.