Êxodo 24
Philoxenus of Mabbug
Êxodo 24:18
And like this holy man the blessed Moses also was twice deemed worthy to go unto the thick darkness and to receive the law upon the tablets; and he was made pure by fasting like unto this, and then he was deemed worthy of the terrible sight. — 13 Ascetic Discourses, Discourse 11 -- On Abstinence