Numbers 11:28

Destroy them. Burden them with communal responsibility, and they will destroy themselves. Another interpretation: Detain them in prison, because they prophesied that Moshe would die and Yehoshua would bring the Israelites into the land.

And Jehoshua bar Nun, the minister of Mosheh, answered and said: Ribboni Mosheh, pray for mercy before the Lord, that the Spirit of prophecy may be withheld from them.

MY LORD MOSES, ‘K’LA’EIM’ (SHUT THEM IN). The meaning of this is that Moses had told the people the words of G-d, that He would take of the spirit which was upon him and put it upon those that will stand with him in the Tent of Meeting. Now those that did not go to the Tent [i.e., Eldad and Medad who had also been designated for that honor], and yet held themselves to be among those upon whom Moses’ spirit had been put [by prophesying in the camp, as Eldad and Medad did], were as rebels against Moses’ words. Therefore Joshua said to Moses, “Shut them in, for perhaps it is a lying spirit in their mouths, or it is an evil spirit that terrifies them, and thus they must be put in a prison like a man that is mad, and maketh himself like a prophet.” But Moses in his humility answered: “Would that all the people of the Eternal were prophets, that the Eternal would give His spirit upon them! — for G-d put His spirit directly upon them without taking of the spirit which was upon me, and would that this would happen to all the people.”
However, from the words of our Rabbis it appears that the custom in Israel was that no one would prophesy about future events in the presence of a prophet who is greater than him, but they would follow him as his disciples, and these were the sons of the prophets. as “those who sought the prophetic gift. And although they directed their minds towards it, the Divine Spirit might or might not rest upon them” (Hilchoth Yesodei Hatorah 7:5). Thus the Rabbis have said in Tractate Sanhedrin [with reference to the prophecy of Eldad and Medad]: “We can well understand according to that Sage who said that [Eldad and Medad prophesied that] ‘Moses will die [before entering the Land],’ that Joshua therefore said, My lord Moses, shut them in [since he wished to save Moses from grief]. But according to the Sage who said that [they prophesied] about the quails [that they would come from the sea], why should they be shut in [and not prophesy]? It is because the case resembled that of a pupil who renders a decision in the presence of his master.” Similarly [this was the reason why they were forbidden to prophesy] according to the Sage who says that they prophesied about Gog and Magog. And the Rabbis have mentioned a similar case in Tractate Megillah in the matter of Deborah. But Moses said that he, being the master, foregoes the honor due to him [and the law is that a Rabbi …

מבחוריו, as if the Torah had written: מנעוריו, ever since his youth. We find the expression בחור for a young person also in Kohelet 11,9 בימי בחורותיך, “in the days of your youth.” On the other hand, in Isaiah 9,16 the line על כן על בחוריו לא ישמח ה', the word is not used in a complimentary way as here, but G’d is portrayed as scorning the follies of the young and immature in spirit.

כלאם, “arrest them!” in the same sense as Genesis 8,2 ויכלא הגשם, “the rain stopped, was arrested.” Some grammarians consider the construction as parallel to שמעני when Avraham implores Efron saying “listen to me!” (Genesis 23,6) and as parallel to Deuteronomy 32,10 ימצאהו, “it has been found.”

אדוני משה כלאם!, he thought that the reason why these two men had not come to the tent of Meeting was because they wanted to demonstrate that they could prophesy without being within the spiritual sphere and physical presence of Moses.

!ויאמר: אדוני משה כלאם, he said: “my lord Moses”. lock them up!” according to the plain meaning of the text, that only seventy elders were to be chosen according to G–d, the man described here as הנער, assumed that these two men must be false prophets, as there were already seventy such men apart from Eldod and Meydod. As a result, they deserved to be locked up pending judgment by the court.