Matthew 26:16

The opportunity which Judas sought is further explained by Luke, how he might betray him in the absence of the multitude; (Luke 22:6.) when the populace was not with Him, but He was withdrawn with His disciples. And this he did, delivering Him up after supper, when He was withdrawn to the garden of Gethsemane. And from that time forward, such has been the season sought for by those that would betray the word of God in time of persecution when the multitude of believers is not around the word of truth.

"From then on he sought an opportunity to betray him." Luke's Gospel shows most clearly the kind of opportunity for which Judas was looking when it says, "And he sought an opportunity to betray him in the absence of the crowds," that is, when the people were not with him but when he was alone with his disciples. His betrayer did the deed after supper, when Christ was alone in the garden of Gethsemane. For once Judas reached his agreement with the Jews, he determined that his opportunity would come when Jesus was not with the crowds. Notice how even today the betrayers of Jesus Christ, Word of truth and Word of God, see their best opportunity to hand him over at a time when Christians are being persecuted.… They are at their worst when the number of his faithful is at its fewest. And since there is a time for all things, for Solomon said "there is a time to be born and a time to die," the time for betraying the Word of truth was specifically when very few of the faithful were with Christ.

"Then went one of the twelve, he that was called Judas Iscariot, unto the chief priests, and said unto them, What will ye give me, and I will deliver Him unto you?" Then. When? When these things were spoken, when He had said, it is for my burial, and not even thereby was he moved to compunction, neither when he heard that the Gospel should be preached everywhere did he fear (and yet it was the language of unspeakable power), but when women showed so much honor, and women that had been harlots, then he wrought the devil's works. But what can be the reason they mention his surname? Because there was also another Judas. And they do not shrink from saying, He was of the twelve; so entirely do they hide none of those things which seem to be matters of reproach. And yet they might have said merely this, that he was one of the disciples, for there were others besides. But now they add, of the twelve, as though they had said, of the first company of those selected as the best, of them with Peter and John. Because for one thing did they care, for truth alone, not for concealing what things were done. For this cause many of the signs they pass by, but of the things that appear to be matters of reproach they conceal nothing; but though it be word, though it be deed, though it be what you will of this kind, they proclaim it with confidence. And not these only, but even John himself, who utters the higher doctrines. For he most of all tells us of the affronts and the reproachful things that were done unto Him. And see how great is the wickedness of Judas, in that he comes unto them of his own accord, in that he does this for money, and for such a sum of money. But Luke saith, that he conferred with the chief captains. For after that the Jews became seditious, the Romans set over them those that should provide for their good order. […]

And from thenceforth he sought opportunity to betray him. Here is set forth the solicitude. And why did he do this? So that he might carry out the crime more easily and more secretly, as it is with sinners, because every one that doth evil …

"He sought an opportunity" to betray Him to them when He was alone, for they feared the multitude, and for this reason they paid Judas to inform them when Jesus would be alone.