It was night - It was in the evening, or early part of the night. What is recorded in the following chapters took place the same night.

He - went immediately out: and it was night - He set off to Jerusalem from Bethany, which was about two miles distant; and, under the conduct of the prince of darkness, and in the time of darkness, he did this work of darkness.

He then having, received the sop,.... As soon as ever he received it, he
went immediately out; fearing lest an entire discovery should be made, and he be prevented accomplishing his design; or being more violently stirred up to it by, Satan, who after the sop entered into him, he directly went from Bethany to Jerusalem, to the chief priests, there, in order to consult and agree upon the delivery of him into their hands:
and it was night; this circumstance is added, to show how eagerly he was bent upon it; that though it was night, it did not hinder or discourage him from setting out on his journey to Jerusalem; and as this was a work of darkness, the night was the fittest time for it, and was a proper emblem of the blackness of the crime he was going to perpetrate.

He then, having received the sop, went immediately out--severing himself for ever from that holy society with which he never had any spiritual sympathy.
and it was night--but far blacker night in the soul of Judas than in the sky over his head.

Went immediately out. It is probable that the Lord's Supper was instituted, at this point, after Judas went out. It was, as we learn from Matthew, after the passover. Matthew's order (see Matt., chap. 26) is as follows: (1) The Passover; (2) the Exposure of Judas; (3) the Lord's Supper. This is John's order, save that he omits, because well known, to record the origin of the Lord's Supper here, and simply tells of the departure of Judas.

He went out - To the chief priests. But he returned afterward, and was with them when they ate the passover, Matthew 26:20, though not at the Lord's Supper.