Exodus 19:15-17 Holman Christian Standard Bible (HCSB)
15 He said to the people, “Be prepared by the third day. Do not have sexual relations with women.”
16 On the third day, when morning came, there was thunder and lightning, a thick cloud on the mountain, and a loud trumpet sound, so that all the people in the camp shuddered. 17 Then Moses brought the people out of the camp to meet God, and they stood at the foot of the mountain.