1 Corinthians 15:18

"Then they also which are fallen asleep in Christ are perished."

Cross References (ranked by relevance)

And I heard a voice from heaven saying unto me, Write, Blessed are the dead which die in the Lord from henceforth: Yea, saith the Spirit, that they may rest from their labours; and their works do follow them.

1 Thessalonians 4:16

For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first:

1 Corinthians 15:6

After that, he was seen of above five hundred brethren at once; of whom the greater part remain unto this present, but some are fallen asleep.