16It is the Lord Jesus himself who will descend from heaven. When he comes down, he will command all of us believers to rise from their graves. The chief angel will shout loudly , and another angel will blow a trumpet for God. Then (OR, As a result), the first thing that will happen is that the people who trusted in Christ before they died will live again.
1 Thessalonians 4
1 Thessalonians 4:16