Exodus 19:1-6 New King James Version (NKJV)
Israel at Mount Sinai
19 In the third month after the children of Israel had gone out of the land of Egypt, on the same day, they came to the Wilderness of Sinai. 2 For they had departed from Rephidim, had come to the Wilderness of Sinai, and camped in the wilderness. So Israel camped there before the mountain.
3 And Moses went up to God, and the Lord called to him from the mountain, saying, “Thus you shall say to the house of Jacob, and tell the children of Israel: 4 ‘You have seen what I did to the Egyptians, and how I [a]bore you on eagles’ wings and brought you to Myself. 5 Now therefore, if you will indeed obey My voice and keep My covenant, then you shall be a special treasure to Me above all people; for all the earth is Mine. 6 And you shall be to Me a kingdom of priests and a holy nation.’ These are the words which you shall speak to the children of Israel.”
Hebrews 12:18-29 New King James Version (NKJV)
The Glorious Company
18 For you have not come [a]to the mountain that may be touched and that burned with fire, and to blackness and [b]darkness and tempest, 19 and the sound of a trumpet and the voice of words, so that those who heard it begged that the word should not be spoken to them anymore. 20 (For they could not endure what was commanded: “And if so much as a beast touches the mountain, it shall be stoned [c]or shot with an arrow.” 21 And so terrifying was the sight that Moses said, “I am exceedingly afraid and trembling.”)
22 But you have come to Mount Zion and to the city of the living God, the heavenly Jerusalem, to an innumerable company of angels, 23 to the [d]general assembly and church of the firstborn who are registered in heaven, to God the Judge of all, to the spirits of just men made perfect, 24 to Jesus the Mediator of the new covenant, and to the blood of sprinkling that speaks better things than that of Abel.
Hear the Heavenly Voice
25 See that you do not refuse Him who speaks. For if they did not escape who refused Him who spoke on earth, much more shall we not escape if we turn away from Him who speaks from heaven, 26 whose voice then shook the earth; but now He has promised, saying, “Yet once more I [e]shake not only the earth, but also heaven.” 27 Now this, “Yet once more,” indicates the removal of those things that are being shaken, as of things that are made, that the things which cannot be shaken may remain.
28 Therefore, since we are receiving a kingdom which cannot be shaken, let us have grace, by which we [f]may serve God acceptably with reverence and godly fear. 29 For our God is a consuming fire.