ISB ~ 1 Corinthians 15 v20

the first fruits:In the liturgy of ancient Israel the first portion of a crop was offered to God in the Temple as a means of consecrating the whole of the expected harvest (Ex 23:19; Lev 23:10-14). So, too, Christ is not only the first to be raised in glory, but his resurrected humanity is an offering that ensures an entire harvest of believers will be raised as he was (Acts 26:23; Rom 11:15-16).

fallen asleep:A euphemism for biological death (15:6; 1 Thess 4:15).