Cornelius a Lapide

Now he that betrayed Him gave them a sign , saying. Whomsoever I shall kiss , that same is He: hold him fast Lest He escape, as He did at other times. “And lead Him away carefully,” adds S. Mark. For Judas was afraid lest Christ should escape by changing His shape, and that He should thus lose the thirty pieces of silver, which were not as yet given, but only promised. Gave them a sign . That the Roman soldiers might know him. For it was night. And perhaps, as some modems suggest, from His likeness to S. James the Less, His kinsman. I shall kiss . Origen mentions a tradition that Christ had two countenances, one natural, the other assumed at will, as at His transfiguration, and that Judas gave this sign for fear Christ should alter His appearance, so as not to be recognised. But this is a gratuitous assumption, and not to the point, for Judas was not present at the Transfiguration; and even had he been there, he might reasonably fear that Christ might render Himself invisible, as He knew He had done at other times. The true reason is as given above