Wayyikra Rabbah, 20:10, p. 466

Jewish Mysticism
R. Tanhuma said- This teaches that they loosened [the covering of] their heads, their hearts became haughty, and their eyes feasted upon the Presence (we-zanu ‘einehem min ha-shekhinah). R. Joshua of Sikhnin said in the name of R. Levi- Moses did not feast his eyes upon the Presence, yet he derived pleasure from the Presence (neheneh min ha-shekhinah). He did not feast his eyes upon the Presence, as it says, “And Moses hid his face” (Exod. 3-6). Yet he derived pleasure from the Presence, as it says, “Moses was not aware that the skin of his face was radiant” (ibid. 34-30).

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