Chief priests and captains - See the notes at Matthew 26:14. See the account of the bargain which Judas made with them explained in the Matthew 26:14-16 notes, and Mark 14:10-11 notes.
Absence of the multitude - The multitude, "the people," were then favorable to Jesus. He had preached in the temple, and many of them believed that he was the Messiah. It was a hazardous thing, therefore, to take him by force, and in their presence, as they might rise and rescue him. Hence, they sought to take him when "he" was away from the multitude; and as Judas knew of a place where he could be found "alone," they were glad of the opportunity of so easily securing him.

And captains - Among the priests who were in waiting at the temple, some were appointed φυλακες, for a guard to the temple; and over these were Ϛρατηγοι commanding officers: both sorts are mentioned by Josephus, War, b. vi. c. 5. s. 3. Bp. Pearce, See another sense of captains, in the note on Matthew 27:65 (note). Dr. Lightfoot supposes these to have been the captains over the watches; for in three places the priests kept watch and ward in the temple, viz. in Beth Abtenes, in Beth Nitsots, and in Beth Mokad. The Levites also in twenty-one places more, Middoth, chap. i. Though these watches consisted of several persons in each, there was one set over them, as the captain or head of that watch. He thinks that Matthew, Matthew 27:65, refers to one of these: Ye have a watch of your own; let some of them be sent to guard the sepulchre. The captain of the temple, he supposes to have been the chief or head of all these watches; and thus he was captain of the captains. In the same Talmudical tract it is said, The ruler of the mountain of the temple (i.e. captain of the temple) takes his walks through every watch with torches lighted before him: if he found any upon the watch, that was not standing on his feet, he said, Peace be with thee: but if he found him sleeping, he struck him with a stick, and he might also burn his clothes. And when it was said by others, What noise is that in the court? the answer was, It is the noise of a Levite under correction, whose garments they are burning, because he slept upon his watch. This custom casts light on Revelation 16:15 : Behold, I come as a thief: blessed is he that watcheth, and keepeth his garments, lest he walk naked, and they see his shame. It is easy to distinguish this captain of the mountain of the temple from the ruler of the temple, or sagan: the former presided over the guards; the latter over the whole service of the temple. We have them both distinguished, Acts 4:1 : there is the captain of the temple; and Annas, who was the sagan. See Lightfoot.

And he went his way, and communed with the chief priests and (a) captains, how he might betray him unto them.
(a) Those that had the charge of keeping the temple, who were not from among the priests and bishops, as is shown below in (Luke 22:52).

And he went his way,.... From Christ, and the rest of the apostles, out of Bethany; and when it was night, about two miles from Jerusalem, whither he went directly:
and communed with the chief priests and captains; that is, of the temple, as in Luke 22:52 and so the Persic version reads, "the militia of the temple"; and the Syriac version renders it, "the captains of the militia of the temple"; instead of captains, the Ethiopic version, reads "Scribes", and so does the Arabic, and which, adds, "and the soldiers"; but these captains were not Roman officers, or soldiers, but ecclesiastical persons, who presided in the temple, and were heads and governors, over bodies of men employed there, of which sort were the following (i):
"there were fifteen, presidents, or governors in the sanctuary, and so they were appointed for ever over each of these fifteen things, one governor; and they are these: one was over the times, or solemn seasons; the second, over the shutting of the gates: the third, over those that kept watch; the fourth, over the singers; the fifth, over the cymbal, with the rest of the singing instruments; the sixth, over the lots; the seventh over the nests (of doves); the eighth, over the seals, or tickets; the ninth, over the drink offerings; the tenth, over the sick (priests); the eleventh, over the waters; the twelfth, over the business of the shewbread; the thirteenth, over the business of the incense; the fourteenth, over the business of the vail; and the fifteenth, over the business of the priests' garments; and every one of these governors had under him "abundance of men", that so they might prepare the business they presided over.''
These seem rather to be meant, than the watch in the temple; which, though kept in several places, there was but one single person that presided over it; as appears from the above account, and from what follows; and who was called the man of the mountain of the house, or the governor of the temple (k):
"in three places the priests kept watch in the sanctuary, in the house of Abtines, and in the house of Nitzotz, and in the house of Moked, and the Levites in twenty and one places--the man of the mountain of the house, went round every ward with torches burning before him, and every one that was not standing, he said unto him, peace be on thee; and if he found he was asleep, he struck him with his staff, and had power to burn his garments.''
Whence it does not appear to me, that there were heads or captains over every ward, as Dr. Lightfoot suggests, but one over them all; perhaps these captains may be the same with the governors of the temple, as in 1 Esdras:
And Helkias, Zacharias, and Syelus, the governors of the temple, gave to the priests for the passover two thousand and six hundred sheep, and three hundred calves. (1 Esdras 1:8)
Did very carefully oversee the holy works, assisting the ancients of the Jews and governors of the temple. (1 Esdras 7:2)
But be these who they will, Judas it seems was informed where, and upon what they were met together, and he went to them, and conversed with them:
how he might betray him unto them; in the most secret manner, and with, the least noise and disturbance.
(i) Maimon. Hilch. Cele Hamikdash, c. 7. sect. 1, 2. Misu. Shekalim, c. 5. sect. 1, 2. (k) Misn. Middot, c. 1. sect. 1, 2.

Captains - Called captains of the temple, Luke 22:52. They were Jewish officers, who presided over the guards which kept watch every night in the temple.