Then (Good News Bible‘s “it would also mean”) draws a further consequence, not directly from verse 17 but from the basic statement of verse 16.

Those also who have fallen asleep in Christ: the metaphor of “sleep” will be unclear in many languages. Good News Bible‘s translation “the believers in Christ who have died” is much clearer.

Perished here is the opposite of “salvation.” If Christ has not risen from the dead, then the Christian who has died has not been saved, but is lost presumably separated from God.

Alternative translation models for this verse are:
• If Christ has not been raised, it would also mean that the believers in Christ who have died have already perished.

Or:
• If God has not raised Christ from death, it would also mean that the believers in Christ who have died are receiving punishment.

Quoted with permission from Ellingworth, Paul and Hatton, Howard A. A Handbook on Paul’s First Letter to the Corinthians, 2nd edition. (UBS Handbook Series). New York: UBS, 1985/1994. For this and other handbooks for translators see here .