15 According to the Lord’s word, we tell you that we who are still alive, who are left until the coming of the Lord, will certainly not precede those who have fallen asleep.

Read 1 Thessalonians 4:15 Using Other Translations

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 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.
We tell you this directly from the Lord: We who are still living when the Lord returns will not meet him ahead of those who have died.