Pentecost - Shavuot

Mount Sinai

The whole people saw thunder and flame, and the sound of a trumpet, and a mountain smoking; And when they saw [that], the people retreated and stood in the distance.
(Exo.20:18)

And from the throne came lightnings and thunders and voices, and seven lamps of fire burned before the throne, which are the seven spirits of God;
(Rev. 4:5)

It seems that the mountains had a strong impact of fire, part of the mountains are clearly black, the peaks are like melted. It is not surprising that the people of Israel already and did not hope that Moses could live.

18 [Moses] said, "Show me your glory."
19 And he said, I will bring all my glory before thee, and proclaim the name of Jehovah before thee, and I will have mercy on whom I will have mercy, and I will have compassion on whomsoever I should repent.
20 And he said, "You can not see my face, because a man can not see me and stay alive."
21 And the LORD said, "This is my place, stand on this rock;
22 But when my glory passes by, I will set you up in the cleft of the rock, and I will cover you with mine hand, until I have passed through;
23 And when I take My hand, you will see Me from behind, and My face will not be visible.
(Exo. 33:18-23)

Moses saw the glory of God, and this is not a bright flash, but a parade. Not surprisingly, he could not only 40 days not, but also not drink, which is physically impossible.
Now we can observe the consequences of this glory.

New Testament Events

1 When the day of Pentecost came, they were all unanimous.
2 And suddenly there was a noise from the sky, as if from a rushing strong wind, and filled the whole house where they were.
3 And there appeared unto them the dividing tongues, as of fire, and rested one on each of them.
4 And they were all filled with the Holy Spirit, and began to speak in other tongues, as the Spirit gave them to utter.
(Acts 2:1-4)