And he promised - That is, to do it - εξωμολογησε: or, He accepted the proposal. See Wakefield.

And he promised, and sought opportunity to betray him unto them in the (b) absence of the multitude.
(b) Without tumult, doing it without the knowledge of the people who used to follow him: and therefore they indeed waited patiently until they knew he was alone in the garden.

And he promised,.... He undertook to deliver him into their hands; he laid himself under obligation to do it; he faithfully promised he would. The Arabic version renders it, he gave thanks; for the money he received, being well pleased he had made such a bargain; and so the word here used sometimes signifies; and indeed commonly either to confess; or to give thanks, in which latter sense it is used, in Matthew 11:25 but here rather it is to be understood in the sense of promising:
and sought opportunity; the two days following before the passover:
to betray him unto them in the absence of the people: when they were gone from him, and he was alone; but found no opportunity of doing it this way, which they had agreed upon with him, and he had promised, until the night of the passover, when he was alone in the garden with his disciples.

in the absence, &c.--(See Matthew 26:5).