In his social history of Christian liturgy, Lutheran liturgist Frank Senn describes the invention of the pax board in England during the 13th century: “This popular practice was welcomed by the clergy and disseminated throughout Christendom by the Franciscans. The pax board was a cross or painted picture of Christ, which the priest kissed after the greeting Pax domini sit semper vobiscum (The peace of the Lord be with you always). It was then kissed by another minister or the parish clerk and passed through the congregation, each person kissing it in turn. Kissing the pax signified that all those present had made peace with one another before coming to the mass.”

The instinct is right: Before coming to the table, we should kiss Christ. But Christ became flesh, not wood, and the most obvious way to kiss Christ is to turn and give your quite-fleshy neighbor in the pew a big smack on the cheek.