Holy communion (also referred to as the Eucharist) is a practice that is common in various sects of Christianity, where believers in a worship service partake in eating a small portion of bread and wine as either emblems of Jesus Christ's sacrificial death on the cross, or (as seen in Catholicism) as the emblems being made into the body and blood of Jesus through the priest calling for a blessing on the emblems. Most Christian denominations use what is called matzo, a type of unleavened bread, while in modern Catholicism, a wafer called a "host" is used in place of bread. It is modeled after the last supper, the Passover, that Jesus partook with His disciples shortly before His death.
In Left Behind: World At War, Rayford, Buck, Chloe, and Bruce performed the ritual on what would be the final hours of Chloe and Bruce's life as they had contracted the biological disease that Nicolae Carpathia had unleashed on believers through tainted shipments of Bibles. Bruce died after the bread portion of the ritual was performed, but when the wine portion took place, Chloe found out that wine was the antidote for the biological disease.