Jewish Mysticism
Commenting on the passage in the morning liturgy, “David blessed the Lord in front of all the assemblage; David said, Blessed are You, Lord, God of Israel our father, from eternity to eternity” (cf. 1 Chron. 29-10)-

In a similar vein [to the opening of David’s blessing] in all generations people say each and every day “Blessed are You, Lord,” for it is written, “I have blessed the Lord before me always” (Ps. 16-8). The Lord is the all in all things. Therefore it says, “Blessed are You, Lord,” like one who speaks [to another] mouth to mouth. “God of Israel,” this refers to the glory that Israel the elder [i.e., Jacob] and all the prophets saw. This is a glorious form, a resplendent light without image except as it appears in the human imagination (be-mar’eh ’adam ha-dimyon). Lest one be startled if one sees [the glory] in another matter, the glory surrounds the prophet in a cloud all the time that it speaks with him. This should not be transmitted in writing but rather mouth to mouth, as the pious one did. The glory of God is not to investigate lest one’s heart be led astray to falsehood. It is written, “the glory of God is to conceal the matter” (Prov. 25-2).

Translated by Elliot Wolfson in Through a Speculum that Shines- Vision and Imagination in Medieval Jewish Mysticism, Princeton- Princeton University Press, 1994.