Answer
In 1 Thessalonians 4, Paul offers a message of hope to the Thessalonians. Elsewhere in his letter, Paul had commended Thessalonian believers for their faith and love (1 Thessalonians 3:6; 5:8), but it seems he wanted to help them grow in their hope. Paul provides for his readers an outline of the future so they might not grieve as those who have no hope (1 Thessalonians 4:13).
As part of that future panorama, Jesus will descend with the voice of the archangel (1 Thessalonians 4:16). Paul explains that Jesus will return for believers who remain until that point in time. In 1 Thessalonians 5, Paul instructs his readers about how Jesus will afterward return in judgment of those who remain on the earth (1 Thessalonians 5:2–4). Believers are not destined for that judgment or wrath to come (1 Thessalonians 5:9)
Paul did not want the Thessalonians to be ignorant of what would take place in the future so that they would have hope (1 Thessalonians 4:13). In particular, he didn’t want them to grieve hopelessly at the loss of saved loved ones who had already died. As surely as Jesus died and rose from the dead, God will bring with Him all those who had died in Christ Jesus (1 Thessalonians 4:14).
When Jesus returns for His own, He will descend with the voice of the archangel (1 Thessalonians 4:16). Believers who are alive and remain when Jesus returns will be caught up with Him in the air (1 Thessalonians 4:17). Heralding that event will be Jesus’ descent with a shout, with the voice of the archangel, and with the trumpet of God (1 Thessalonians 4:16). Those who have already died and whose spirits are with the Lord will come back in the clouds with Jesus (1 Thessalonians 4:14), and their bodies will be raised and glorified first (1 Thessalonians 4:16). Then all who remain will be caught up with them, and they will be together with the Lord (1 Thessalonians 4:17). This message comforts believers and provides hope even when believers are faced with death (1 Thessalonians 4:18).
Believers in Christ can look forward in hopefulness to the day when Jesus will descend with the voice of the archangel. There are two mentions of archangels (or “first” angels) in the New Testament. One is in 1 Thessalonians 4:16. The second, in Jude 1:9, identifies Michael as “the archangel.”
In Daniel 12 the angel Gabriel told Daniel that Michael will “arise” one day, and then would come a time of severe distress from which many of Daniel’s people would be rescued (Daniel 12:1). Perhaps this indicates that Michael will be present when Jesus returns in the clouds at the rapture. According to 1 Thessalonians 4:16, Michael’s vocalizing will be among the events of the rapture (or the “catching up,” described in 1 Thessalonians 4:13–17). Alternately, the statement that Jesus will descend with the voice of the archangel could simply indicate that Jesus’ voice would be like that of an archangel, since the phrase can literally be translated “in the voice of an archangel.”
Paul explains that there will be three audible signifiers of this event: the shout, the voice of an archangel, and the last trumpet. It seems most likely that the statement that Jesus will descend with the voice of an archangel simply describes concurrent events that will take place when Jesus returns for those who have believed in Him.