Matthew 26:4

And consulted that they might take Jesus by subtilty - The providence of God frustrated their artful machinations; and that event which they wished to conduct with the greatest privacy and silence was transacted with all possible celebrity, amidst the thousands who resorted to Jerusalem, at this season, for the keeping of the passover. It was, doubtless, of the very first importance that the crucifixion of Christ, which was preparatory to the most essential achievement of Christianity, viz. his resurrection from the grave, should be exhibited before many witnesses, and in the most open manner, that infidelity might not attempt, in future, to invalidate the evidences of the Christian religion, by alleging that these things were done in a corner. See Wakefield in loco.

By subtlety - 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, lest the people should rise and rescue him. They were probably aware that he had gone out to Bethany, or to some place adjacent to the city; and as he passed his nights there and not in the city, there was need of guile to ascertain the place to which he had retired, and to take him.