“When Judas came,
He went up
Then he kissed him.”
καὶ ἐλθὼν εὐθὺς προσελθὼν αὐτῷ λέγει Ῥαββεί, καὶ κατεφίλησεν αὐτόν·
This is almost word for word in Matthew, chapter 26:49. In Luke, chapter 22:47, there is an abbreviated form of only Judas kissing Jesus, while in John, chapter 18, there is no Judas kiss at all. Mark said that Judas suddenly came up to Jesus (καὶ ἐλθὼν εὐθὺς προσελθὼν αὐτῷ). Then Judas called Jesus “Rabbi (λέγει Ῥαββεί)!” Then he kissed Jesus (καὶ κατεφίλησεν αὐτόν). Notice that both Matthew and Mark used the Jewish title of Rabbi. The kiss would have been the normal greeting, since it was certainly used by Christ’s followers, as indicated in the Pauline letters. Yet it might also have been a practical way for others to recognize Jesus in the dark.