" And the Lord told Moses, "Go to the people and consecrate them today and tomorrow. They must wash their clothes and be prepared by the third day, for on the third day the Lord will come down on Mount Sinai in the sight of all the people. ...... 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. Then Moses brought the people out of the camp to meet God, and they stood at the foot of the mountain. Mount Sinai was completely enveloped in smoke because the Lord came down on it in fire. Its smoke went up like the smoke of a furnace, and the whole mountain shook violently. As the sound of the trumpet grew louder and louder, Moses spoke and God answered him in the thunder." ( Exodus 19: 10-20 )

I remember as a child, watching the movies of the launch of the Saturn V rocket that carried the Apollo spacecraft to the moon, and even now, it is an awe inspiring sight. I can almost feel the thunder, the rumbling, the shaking, the heat of the rocket fuel and see the billowing clouds of smoke that accompany the delivery of the vast amounts of energy required to propel a few humans to the heavens. When I read the Exodus account those memories return in all their vividness, only this time, it is the descent of God Himself ( or as much of His infinity as He chose ) on a mountain in Sinai that is the event. Small wonder that the people of Israel were absolutely terrified - after all - this was the God that they had seen rain down death and destruction on the Egyptians through the plagues, and the one who parted the sea for them! Here He is, speaking to Moses.

This is the same God who manifested His presence to Elijah as well- look at how that went down- " At that moment, the Lord passed by. A great and mighty wind was tearing at the mountains and was shattering cliffs before the Lord, but the Lord was not in the wind. After the wind there was an earthquake, but the Lord was not in the earthquake. After the earthquake there was a fire, but the Lord was not in the fire. And after the fire there was a voice, a soft whisper. When Elijah heard it, he wrapped his face in his mantle and went out and stood at the entrance of the cave." - 1 Kings 19:11-13

Very similar, but we should be careful not to mistake the the thunder, lightning, earthquake, smoke, fire, trumpet for the voice/presence of the Lord. Remember the burning bush when God spoke to Moses? That was Holy ground sanctified by His presence - and He spoke to Moses much as He did to Elijah in the text above - in a voice that could be listened to and endured by a human. He chooses how to interact with us.
The awesome power and majesty of God is seldom revealed in the Word - apart from these two occasions - the books of Isaiah (Chap 6), Ezekiel (Chap 1) , and Revelation (Chap 4) are other places you can go to get even an idea of the complete Otherness of a Person from whose presence Earth and Heaven flee! ( Rev 20:11 ) forget about a little shaking and shuddering of a mountain or cliff.

God underscored the giving of His Law to His people with an event that they should never ever have forgotten. It is a testament to the power of sin and the work of the enemy that these images and experiences were gradually wiped from their memory, and those of their children - and in today's day and age, have been almost completely erased from that of the next generation. We have replaced an awesome, terrible, infinite, majestic God with an indulgent forgiving Santa Claus who loves us no matter what we do, and just wants us to be happy and rich or even worse, an old guy with a beard who appears to be completely irrelevant and unnecessary to modern life.

God is not who we want Him to be. He Is Who He Is.

It's our attitudes that need adjusting to understand that God is extremely serious about EVERY SINGLE WORD that proceeds out of His mouth, and it is with this reverent and teachable attitude that we shall begin our journey through His Law.

I would just like to draw your attention to the fact that the Law was revealed on the third day. What a wonderful picture and shadow of Christ! What rejoicing and triumph must have there been in Heaven when He was resurrected!
His first appearance to His people was to stand in front of the women (!- shame on the male disciples) who came to the tomb - reversing the shame of Eves deception with the honor of being the first witnesses of the fulfillment of the Genesis promise, confirming the ripping apart of the veil to Gods Most Holy presence, the breaking down of the boundary placed around Mt. Sinai and the writing of the Law in our hearts and not on tablets of stone. The still small voice of God is now within us!

Our God is indeed beyond anything we can ever imagine or conceive! Hallelujah!!!