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). צאו שלשתכם GO OUT YOU THREE [UNTO THE APPOINTED TENT] — This tells us that the names of all three of them were mentioned as one utterance, something that is impossible for a human mouth to articulate and a human ear to catch (Sifrei Bamidbar 102).

וַיֹּ֨אמֶר יְהֹוָ֜ה פִּתְאֹ֗ם אֶל־מֹשֶׁ֤ה וְאֶֽל־אַהֲרֹן֙ וְאֶל־מִרְיָ֔ם צְא֥וּ שְׁלׇשְׁתְּכֶ֖ם אֶל־אֹ֣הֶל מוֹעֵ֑ד וַיֵּצְא֖וּ שְׁלׇשְׁתָּֽם׃

And the Lord spoke suddenly to Moshe, and to Aharon, and to Miryam, Come out you three to the Tent of Meeting. And they three came out.