In 1 Corinthians 15:6, Paul notes some witnesses have 'fallen asleep'—the same group whose fate hinges on the resurrection in verse 18.

In 1 Cor 15:51, Paul continues with the 'sleep' metaphor, clarifying that not all will die but all will be transformed.

In 1 Thessalonians 4:13, believers who die have hope—the opposite of being lost if no resurrection, reinforcing the stakes.

In 1 Thessalonians 4:14, Christ's resurrection assures that those who fell asleep in him will be raised—directly answering the loss Paul hypothesizes here.

John 11:11 uses the same 'fallen asleep' metaphor for Lazarus, illustrating the euphemism Paul employs for believers.

John 11:25 declares Jesus as resurrection and life — directly countering Paul's hypothetical that believers who died have perished.

Acts 7:60 describes Stephen's death as 'fell asleep' — a parallel usage of the same metaphor for a believer's death.

In Revelation 14:13, the dead who die in the Lord are blessed—showing the positive outcome that contradicts the hypothetical loss if no resurrection.

Acts 13:36 says David 'fell asleep' — same euphemism, but applied to an OT figure, not specifically 'in Christ'.