"At that time the sign of the Son of Man will appear in the sky, and all the nations of the earth will mourn. They will see the Son of Man coming on the clouds of the sky, with power and great glory. 31 And he will send his angels with a loud trumpet call, and they will gather his elect from the four winds, from one end of the heavens to the other.
1 Corinthians 15:50-53
I declare to you, brothers, that flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable. 51 Listen, I tell you a mystery: We will not all sleep, but we will all be changed— 52 in a flash, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, the dead will be raised imperishable, and we will be changed.
1 Thessalonians 4:13-18
Brothers, we do not want you to be ignorant about those who fall asleep, or to grieve like the rest of men, who have no hope. 14 We believe that Jesus died and rose again and so we believe that God will bring with Jesus those who have fallen asleep in him. 15 According to the Lord's own word, we tell you that we who are still alive, who are left till the coming of the Lord, will certainly not precede those who have fallen asleep. 16 For the Lord himself will come down from heaven, with a loud command, with the voice of the archangel and with the trumpet call of God, and the dead in Christ will rise first. 17 After that, we who are still alive and are left will be caught up together with them in the clouds to meet the Lord in the air. And so we will be with the Lord forever. 18 Therefore encourage each other with these words.
"There will be no more delay! 7 But in the days when the seventh angel is about to sound his trumpet, the mystery of God will be accomplished, just as he announced to his servants the prophets."
15 The seventh angel sounded his trumpet, and there were loud voices in heaven, which said:
"The kingdom of the world has become the kingdom of our Lord and of his Christ,
and he will reign for ever and ever."
16 And the twenty-four elders, who were seated on their thrones before God, fell on their faces and worshiped God, 17 saying:
"We give thanks to you, Lord God Almighty,
the One who is and who was,
because you have taken your great power
and have begun to reign.
18 The nations were angry;
and your wrath has come.
The time has come for judging the dead,
and for rewarding your servants the prophets
and your saints and those who reverence your name,
both small and great —
and for destroying those who destroy the earth."
That seventh angel sounding is the last mention of any kind of "trumpet" in the Bible, it is "the last trumpet."