Exodus 24:12-18 New Revised Standard Version (NRSV)
12 The Lord said to Moses, “Come up to me on the mountain, and wait there; and I will give you the tablets of stone, with the law and the commandment, which I have written for their instruction.” 13 So Moses set out with his assistant Joshua, and Moses went up into the mountain of God. 14 To the elders he had said, “Wait here for us, until we come to you again; for Aaron and Hur are with you; whoever has a dispute may go to them.”
15 Then Moses went up on the mountain, and the cloud covered the mountain. 16 The glory of the Lord settled on Mount Sinai, and the cloud covered it for six days; on the seventh day he called to Moses out of the cloud. 17 Now the appearance of the glory of the Lord was like a devouring fire on the top of the mountain in the sight of the people of Israel. 18 Moses entered the cloud, and went up on the mountain. Moses was on the mountain for forty days and forty nights.
Matthew 17:1-9 New Revised Standard Version (NRSV)
17 Six days later, Jesus took with him Peter and James and his brother John and led them up a high mountain, by themselves. 2 And he was transfigured before them, and his face shone like the sun, and his clothes became dazzling white. 3 Suddenly there appeared to them Moses and Elijah, talking with him. 4 Then Peter said to Jesus, “Lord, it is good for us to be here; if you wish, I[a] will make three dwellings[b] here, one for you, one for Moses, and one for Elijah.” 5 While he was still speaking, suddenly a bright cloud overshadowed them, and from the cloud a voice said, “This is my Son, the Beloved;[c] with him I am well pleased; listen to him!” 6 When the disciples heard this, they fell to the ground and were overcome by fear. 7 But Jesus came and touched them, saying, “Get up and do not be afraid.” 8 And when they looked up, they saw no one except Jesus himself alone.
9 As they were coming down the mountain, Jesus ordered them, “Tell no one about the vision until after the Son of Man has been raised from the dead.”