Now we do not want you to be ignorant, brothers, concerning those who have fallen asleep, so that you will not grieve as also the rest, who have no hope.
References for 1 Thessalonians 4:13
For if we believe that Jesus died and rose [again], thus also God will bring those who have fallen asleep through Jesus together with him.
For this we say to you by the word of the Lord, that we who are alive, who remain until the Lord's coming, will not possibly precede those who have fallen asleep.
For the Lord himself will descend from heaven with a shout of command, with the voice of the archangel and with the trumpet of God, and the dead in Christ will rise first.
Then we who are alive, who remain, will be snatched away at the same time together with them in the clouds for a meeting with the Lord in the air, and thus we will be together with the Lord always.
Therefore comfort one another with these words.