John Calvin on Matthew 26:49

49. Hail, Rabbi. I have no doubt that Judas, as if trembling for his Master’s danger, pretended by these words to have some feeling of compassion; and, accordingly, in Mark a pathetic repetition is expressed, “Il y a une repetition comme d’un homme parlant de grande affection;” — “there is a repetition, as if by a man who spoke from strong feeling.” Rabbi, Rabbi. For though he was impressed with the majesty of Christ, still the devil so fascinated his mind, that he felt assured that his treachery was concealed by a kiss, and by soothing words. This salutation, or exclamation, therefore, was a pretense of compassion. I offer the same opinion about the kiss; for though it was a very common practice among the Jews to welcome friends with a kiss, yet as Judas had left Christ but a little before, he seems now — as if he had become suddenly alarmed at his danger — to give the last kiss to his Master. Thus he excels the rest in the appearance of affection, when he appears to be deeply grieved at being separated from his Master; but how little he gained by his deception is evident from Christ’s reply.