וַיֹּ֤אמֶר לּוֹ֙ מַלְאַ֣ךְ יְהוָ֔ה לָ֥מָּה זֶּ֖ה תִּשְׁאַ֣ל לִשְׁמִ֑י וְהוּא־פֶ֛לִאי׃ (ס)
Der Engel des Herrn sprach zu ihm: Warum doch fragst du nach meinem Namen, da er verborgen ist?
Rashi on Judges
When it is mystical. It is concealed. It changes constantly,4According to the angel’s mission at that particular time. Cf. Rashi to Bereishis, 32:30. so that its identity remains unknown on any given day.