Leviticus 23:23 Yahweh spoke to Moses, saying, 24 “Speak to the children of Israel, saying, ‘In the seventh month, on the first day of the month, there shall be a solemn rest for you, a memorial of blowing of trumpets, a holy convocation. 25 You shall do no regular work. You shall offer an offering made by fire to Yahweh.’”
The trumpet sounds, calling everyone to cease from their labors and to assemble to worship God. In the New Covenant this is fulfilled at the end of time on that glorious day when God assembles all of his children together.
For the trumpet will sound, the dead will be raised imperishable, and we will be changed. For the perishable must be clothed with the imperishable, and the mortal with immortality. 1 Corinthians 15:52-53