John 18:28

The hall of judgment] RV 'the palace,' lit. 'the prætorium,' here indicates the official residence of Pilate, which was either the castle of Antonia or a palace built by Herod on the W. hill of Jerusalem: see Matthew 27:27. Pilate's judgment-seat was in the open air, but he more than once entered the building to confer with Jesus privately (John 18:33; John 19:9).

That they might not be defiled (RV)] A Gentile house would not have been purged from the presence of leaven in prospect of the Passover, and therefore by entering it they would have defiled themselves. St. John, who had already eaten the Passover with Jesus, was apparently not so scrupulous: he entered, and hence was able to report the conversations between our Lord and Pilate (John 18:33 chapter John 19:9).

But.. might eat the passover] It is obvious that St. John places the Jewish Passover, not on Thursday evening, as the synoptists seem to do, but on Friday evening, and regards the Last Supper on Thursday night as an anticipated Passover—a Passover eaten before the legal date, because Jesus knew that He was to suffer on the morrow. Some critics, however, following the primâ facie meaning of the synoptists, date the Jewish Passover on Thursday evening, and understand the expression here ('but might eat the Passover') to refer not to the Passover proper, but to the 'chagigah,' a sacrifice offered on the morning after the paschal meal: see on Matthew 26:17.