Origen

If it be asked why Judas betrayed Jesus with a kiss, according to some it was because He desired to keep up the reverence due to his Master, and did not dare to make an open assault upon Him; according to others, it was out of fear that if he came as an avowed enemy, he might be the cause of His escape, which he believed Jesus had it in His power to effect. But I think that all betrayers of truth love to assume the guise of truth, and to use the sign of a kiss. Like Judas also, all heretics call Jesus Rabbi, and receive from Him mild answer. And Jesus said unto him, Friend, wherefore art thou come? He says, Friend, upbraiding his hypocrisy; for in Scripture we never find this term of address used to any of the good, but as above, Friend, how camest thou in hither? (Matt. 22:12.) and, Friend, I do thee no wrong. (Matt. 20:13.)