The New Testament often uses the word, “sleep,” when referring to death. When Lazarus had died, Jesus said that he had merely “fallen asleep” (John 11:11). When Jairus’ daughter died, Jesus said, “The child has not died, but is asleep” (Mark 5:39). Paul used the same terminology to describe believers who had died. He said that they “have fallen asleep in Jesus” (1 Thessalonians 4:14).
Behind this metaphor in each of these passages is hope. The one who is sleeping will rise again. Indeed, those who have believed in Jesus will be raised to eternal life. So, when a believer dies, we do not need to grieve as the rest who have no hope (1 Thessalonians 4:13).