66 Concerning the resurrection of the righteous, Paul also speaks thus in writing to the Thessalonians: “We would not have you to be ignorant concerning them which are asleep, that you sorrow not even as others which have no hope. For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with Him. For this we say unto you by the word of the Lord, that we which are alive (and) remain unto the coming of the Lord, shall not prevent them which are asleep. For the Lord Himself shall descend from heaven with a shout, with the voice and trump of God, and the dead in Christ shall rise first. Then we which are alive (and) remain shall be caught up together with them in the clouds to meet the Lord in the air; and so shall we ever be with the Lord.”
Source: The Antichrist (New Advent)