Albert Barnes Commentary Matthew 26:4

"and they took counsel together that they might take Jesus by subtlety, and kill him." — Matthew 26:4 (ASV)

By subtlety. That is, by guile, deceit, or in some secret manner, so that the people would not know it.

Jesus was regarded by the people as a distinguished prophet, and by most of them probably as the Messiah; and the Sanhedrin did not dare to take him away openly, for fear that the people would rise and rescue him.

They were probably aware that he had gone out to Bethany, or to some of the places near the city. Since he spent his nights there, and not in the city, there was need of guile to ascertain the place where he was staying, and to seize him.