Judah ben Barzillai al-Barceloni, Perush Sefer Yesirah, pp. 34-35

Jewish Mysticism
Since [the other prophets] did not have the same capacity in their eyes and hearts as did Moses our master, [the glory] appeared to them from within these images (mar’ot), for they see their forms as the form of an anthropos. Sometimes they see them in the form of an elder and sometimes in the form of a youth. All these appearances are for them [mental] images (dimyonot) and not a [physical] vision (re’iyah). Just as there is no person in the mirror or glass [reflecting someone’s image] so there is no form of a person within those lights [that come forth from the created glory]. By means of those great lights which they [the prophets] see there appears to them within these forms a form of an anthropos glorious in power, in the great light and in strength. This comes to them on account of the weakness and feebleness of their eyes and hearts like a person whose vision is weak so that he sees that which is low as if it were high and that which is one as if it were two. Thus it is written, “and spoke parables through the prophets” (Hosea 12-11), for they are [mental] images and not a [physical] vision. But with respect to Moses, whose mind and heart were refined and whose eyes were brighter than all other people, the Holy One, blessed be He, showed him His splendor and His glory, which He created for the honor of His name, for it is greater than all the other lights which the prophets saw. [Moses] looked at the end of the splendor of the Shekhinah, which is the great created light, and he had the visual capacity to see it with an actual vision (re’iyah mamash) and not [through] visions, dreams or images. Therefore he saw, knew and discerned that there is no form of an anthropos there or any other [corporeal] form except the form of the splendor, the light, and the created great fire which is the form of the great light whose beginning no man can see.

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