Deuteronomy 16:3

16:3 You must not eat any yeast with it; for seven days you must eat bread made without yeast, symbolic of affliction, for you came out of Egypt hurriedly. You must do this so you will remember for the rest of your life the day you came out of the land of Egypt.

Deuteronomy 33:2

33:2 He said:

A Historical Review

The Lord came from Sinai

and revealed himself to Israel from Seir.

He appeared in splendor from Mount Paran,

and came forth with ten thousand holy ones.

With his right hand he gave a fiery law to them.