Betrayer: see verse 15 for a discussion of “betray.” As in verse 25, Judas in referred to as the betrayer, a fact which Matthew will not let his readers forget (see 27.3). Mark also keep this description before the eyes of his readers (Mark 14.42, 44), though it is apparently absent from Luke and John.
“The crowd” of Good News Translation translates them of the Greek text. However, the nearest antecedent is “the chief priests and the elders” and not the “great crowd” mentioned earlier in verse 47. Most translations do not specifically identify the antecedent, though Bible en français courant follows Good News Bible in doing so.
Sign (Good News Translation “signal”) is used elsewhere in the Gospel with the extended meaning of “miracle” (see its use at 12.38). The city of Jerusalem and the region around Jerusalem overflowed with pilgrims during the time of Passover. This may be why it was necessary for Judas to give a prearranged signal to identify Jesus to the people who were sent out to arrest him. But another reason may be that he did not want to make it obvious that he was betraying Jesus.
To greet someone with a kiss, whether on the hand or foot, was a show of respect, the equivalent of using an honorific. Of course, the text does not say where Judas kissed Jesus, and neither should the translation. Die Bibel im heutigen Deutsch defines the kiss as “a kiss of greeting,” which is perhaps the best example to follow.
Seize (so also New English Bible, Moffatt, An American Translation) may also mean “Arrest” (Good News Translation, New International Version). Seize him is rendered rather dynamically by Phillips: “Get him!”
It is often better to use indirect discourse in this verse; for example, “The traitor had told them that he would signal to them which person they should arrest, by kissing him (in greeting)” or “The traitor had told them that when he gave a kiss of greeting to someone, that would be the person to arrest.”
Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on the Gospel of Matthew. (UBS Handbook Series). New York: UBS, 1988. For this and other handbooks for translators see here .