1Thessalonians 4:14 For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him. 

‘Died and rose again.’ The death of Jesus Christ is the assurance of salvation for all who will believe (Matt. 26:28; Rom. 5:6-11; 1Pet. 2:24). The resurrection of Jesus Christ is the assurance of resurrection for all men (5:10; John 14:19; Rom. 5:10; 6:5-8; 1Cor. 15:4-23; 2Tim. 2:11).

‘Sleep in Jesus’ – Body-sleep, is not soul-sleep: Sleep means the death of the body (4:14-16; 5:10; Deut. 31:16; 2Sam. 7:12; 1Kin. 1:21; Job 7:21; Ps. 13:3; Dan. 12:2; Mark 5:39; Luke 8:52; John 11:11-14; Acts 13:36; 1Cor. 11:30; 15:51; Jas. 2:26). These are all the passages where the word “sleep” is found in connection with the death. The word “slept” is used in Matthew 27:52 and 1Corinthians 15:20 of death, and the phrase “slept with his fathers” is used 36 times of death in the Old Testament. Not one time is it stated that the soul sleeps. The soul is immortal (1Pet. 3:4). The term “sleep in Jesus” simply refers to those who were in Christ at their death (4:14, 16).

‘Bring with him.’ Christians at death go immediately to paradise to await the resurrection of their sleeping bodies (2Cor. 5:8; Php. 1:21-24; Heb. 12:22-23; Rev. 6:9-11). When Christ leaves heaven to come down in the air of the earth (4:17), the saints who are in paradise will come back with Him and be reunited with their bodies which will be resurrected in a moment (1Cor. 15:51-58).