This is the first reference to the event of the giving of the law to Moses and the people. This time will eventually be known as Pentecost, 50 days after coming out of Egypt.
Exodus 19:1 In the third month, when the children of Israel were gone forth out of the land of Egypt, the same day came they into the wilderness of Sinai.
Literally the people will be call priests in the New Testament.
Exodus 19:6 And ye shall be unto me a kingdom of priests, and an holy nation. These are the words which thou shalt speak unto the children of Israel.
1 Peter 2:9 But ye are a chosen generation, a royal priesthood, an holy nation, a peculiar people; that ye should shew forth the praises of him who hath called you out of darkness into his marvellous light:
In my Revelation study: From Reformation to Reformation
We have recently studied this concept as introduced in this verse:
Revelation 1:6 And hath made us kings and priests unto God and his Father; to him be glory and dominion for ever and ever. Amen.
Exodus 19:16 And it came to pass on the third day in the morning, that there were thunders and lightnings, and a thick cloud upon the mount, and the voice of the trumpet exceeding loud; so that all the people that was in the camp trembled.
and the voice of the trumpet exceeding loud; or, “exceeding strong” (w); being blown by the mighty angels, and by ten thousand them, with whom the Lord now descended:
And indeed we shall hear the trumpet sound again….
Mat 24:31 And he shall send his angels with a great sound of a trumpet, and they shall gather together his elect from the four winds, from one end of heaven to the other.
1Co 15:52 In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
Rev 1:10 I was in the Spirit on the Lord’s day, and heard behind me a great voice, as of a trumpet,
Rev 9:14 Saying to the sixth angel which had the trumpet, Loose the four angels which are bound in the great river Euphrates.
Perhaps read more of the Day of the Lord at:
What is the Day of the Lord?
by Mike Ratliff