Matthew
Matthew 26:48ESV·traditional attribution

Now the betrayer had given them a sign, saying, “The one I will kiss is the man; seize him.”

John Calvin Reformed @genevareformer

48. Now he who betrayed him. I have no doubt that Judas was restrained, either by reverence for our Lord, or by shame for his crime, from venturing openly to avow himself as one of the enemies; and the warning which, Mark tells us, he gave the soldiers — to lead the away cautiously, was given, I conjecture, for this reason, that he recollected the...

John Gill Reformed Baptist @doctorgill

And forthwith he came to Jesus,.... As soon as ever he appeared, before the rest could come up; for, he went before them, as Luke says, and that not only as, their guide to direct them to the person they wanted, but he separated himself from them, that it might not be thought that he came with them, or belonged to them: and said, hail, master; and kissed him.

Albert Barnes Presbyterian @notesbybarnes

Verse 48. Gave them a sign. That is, told them of a way by which they might know whom to apprehend, i.e., by his kissing him. It was night. Jesus was, besides, probably personally unknown to the Romans,perhaps to the others also. Judas, therefore, being well acquainted with him, to prevent the possibility of mistake, agreed to designate him by one of the tokens of friendship.