"The betrayer had arranged a signal with them: 'The one I kiss is the man; arrest him.'" — Matthew 26:48
Growing up in North America, I wasn't familiar with the custom in which two adult men would kiss each other in greeting. But as an adult I learned that it was common in many societies around the world. I remember television coverage of leaders of the former Soviet Union as they greeted the leaders of allied nations. In each greeting, the leaders would embrace, pinch the flesh behind each other's cheekbones, and then kiss one another on each side of the face.
However it's done, a kiss involves getting close to someone in a way that is meant to erase all fear of harm or ill will. A kiss is meant to express good things: a peace-filled greeting for the other party; the affection of two people who care for each other; the pledge of permanent love and friendship between a bride and groom; or even the measure of reverence or respect that a bishop expresses when he kisses the ring of the Pope.
After Judas Iscariot made his financial contract to betray Jesus, his friend, master, and teacher, he deliberately chose the kiss as the way to carry out his part in the plot. He chose the symbol of peace, affection, care, friendship, and respect—and transformed it into a kiss of death.
Peace, affection, caring, friendship, respect—Jesus, you are the source of all these blessings. Yet a symbol of all these good things became a signal in the plot to kill you. We sigh with you, Lord. Help us to be faithful. In your name, Amen.