‘And immediately he came to Jesus, and said, “Hail, Rabbi,” and kissed him.'
As Judas arrived on the scene he went immediately to Jesus and kissed him. There was no hesitation. And he said to Him, ‘Hail, Rabbi'. In Matthew the title Rabbi is reserved for Judas' lips, probably in order to indicate that he was still of the old Israel. His disciples called Him ‘Lord'. The aim behind his apparent peaceable approach was probably in order to disarm Jesus and His disciples until it was too late. But he knew very well that he was marking Jesus down for death.
‘Kissed Him.' The word is intensive and signifies kissed effusively. This may have in mind Proverbs 27:6, ‘'the kisses of an enemy are profuse'. But it clearly sickened Matthew. His point was that Judas was not just betraying Jesus. He was enjoying it. This is all the more effective in that none of the narratives speak adversely against Judas other than by a statement of the facts.