When you hear God’s trumpet
“And he will send out his angels with a loud trumpet call, and they will gather his elect from the four winds, from one end of heaven to the other.” (Matt. 24:31 ESV)
At the sound of God’s trumpet the dead shall be raised
“In a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised imperishable, and we shall be changed.
(1 Cor. 15:52 ESV)
At the sound of God’s trumpet Christ shall reign forever and ever
“Then the sixth angel blew his trumpet, and I heard a voice from the four horns of the golden altar before God…” (Rev. 9:13 ESV)
“Then the seventh angel blew his trumpet, and there were loud voices in heaven, saying, “The kingdom of the world has become the kingdom of our Lord and of his Christ, and he shall reign forever and ever.” (Rev. 11:15 ESV)
Therefore…
“But we do not want you to be uninformed, brothers, about those who are asleep, that you may not grieve as others do who have no hope. For since we believe that Jesus died and rose again, even so, through Jesus, God will bring with him those who have fallen asleep. For this we declare to you by a word from the Lord, that we who are alive, who are left until the coming of the Lord, will not precede those who have fallen asleep. For the Lord himself will descend from heaven with a cry of command, with the voice of an archangel, and with the sound of the trumpet of God. And the dead in Christ will rise first. Then we who are alive, who are left, will be caught up together with them in the clouds to meet the Lord in the air, and so we will always be with the Lord. Therefore encourage one another with these words.” (1 Thess. 4:13-18 ESV)