Commentary for Numbers 12:4

פתאם SUDDENLY — He revealed himself to them suddenly just when they were unclean as a result of marital intercourse, so that they cried; “Water, water!” (for purification). He did this to give them to understand that Moses had acted rightly in that he had separated from his wife, since the Shechinah used to reveal Itself to him at all times and there was no definite time fixed for the Divine communication (Midrash Tanchuma, Tzav 13).

AND THE ETERNAL SPOKE ‘PITH’OM’ (SUDDENLY) UNTO MOSES, AND UNTO AARON, AND UNTO MIRIAM. Now Moses was not with them, but [they are mentioned together because] the Divine communication came to the three of them simultaneously. The sense of the word “suddenly” is that they did not direct their minds towards or intend to receive a Divine communication at that time, it being in honor of Moses that it came to them without any preparation for it; for the word pith’om (suddenly) in the opinion of the commentators [as explained in Ibn Ezra] applies to something which one did not think of, from the root pethi (simple-minded). Therefore Scripture uses the term pith’om [only] on account of Aaron and Miriam, for Moses our teacher was fit for a Divine communication at any time, and his mind was prepared to cleave to the Glorious Name at every moment, as our Rabbis have explained in connection with the reason why he [Moses] separated himself from his wife.²⁷³Shabbath 87 a: Since the Divine Glory reveals itself to me at all times [and there is no definite time fixed for the Divine communication] …” Onkelos, however, rendered [the word pith’om] as bithkeiph (in a hurry), the sense being that whilst Miriam and Aaron were still speaking about Moses, and the words were still in their mouths, they were told: Come out ye three unto the Tent of Meeting, and He did not delay [the rebuke] to them at all. The word pith’om is thus a term indicating hurry. Similarly, And I beheld his habitation cursed ‘pith’om’ (suddenly);²⁷⁴Job 5:3. whose breaking cometh ‘pith’om ‘l’pheta’ (suddenly at an instant);²⁷⁵Isaiah 30:13. ‘b’pheta’ pith’om’ (very suddenly),²⁷⁶Above, 6:9. the double expressions being for emphasis, just like: ‘kim’at kot’ (a very little while);²⁷⁷Ezekiel 16:47. ‘harbei m’od’ (exceedingly great).²⁷⁸Genesis 15:1. So also: ‘bi’m'od m’od’ (very much),²⁷⁹Ibid., 17:2. and similar cases. And pethaim (simple-minded ones) are those who are very impetuous, who do not have any deep grasp of a matter and do not reflect on it at all, the usage being similar to the expression and the counsel of the wily is hurried.²⁸⁰Job 5:13. For any plan which is decided upon in a hurry is folly (Rashi). So also: ‘petha’ (on a sudden) shall he be broken;²⁸¹Proverbs 6:15. and if ‘b’phetha’ (suddenly) without enmity,²⁸²Further, 35:22. [which Onkelos renders] bithkeiph, which is like pethi (simple), of the expression pith’om (hurriedly).
The reason [why He said at first] Come out ye three and [then in the following verse it says] and He called Aaron and Miriam [excluding Moses] is that G-d wanted him to be present [in the Tent of Meeting] and to see how He is zealous for Moses’ honor; and so that he would be available [to forgive them], for G-d would not forgive them unless he did, after they would beg him and he agrees to [forgive] them. And He called Aaron and Miriam, in order to tell Moses’ praise when he was not present.

צאו שלשתכם. G’d wanted that Moses should become aware of His being concerned immediately when anyone impugned his honour.