Then came the day of unleavened bread, when the passover must be killed.
All Commentaries on Luke 22:7 Go To Luke 22
Eusebius of Caesarea
AD 339
But should any one say, “If on the first day of unleavened bread the disciples of our Savior prepare the Passover, on that day then should we also celebrate the Passover;” we answer, that this was not an admonition, but a history of the fact. It is what took place at the time of the saving Passion; but it is one thing to relate past events, another to sanction and leave them an ordinance to posterity. Moreover, the Savior did not keep His Passover with the Jews at the time that they sacrificed the lamb. For they did this on the Preparation, when our Lord suffered. Therefore they entered not into the hall of Pilate, that they might not bedefiled, but might eat the Passover. For from the time that they conspired against the truth, they drove far from them the Word of truth. Nor on the first day of unleavened bread, on which the Passover ought to be sacrificed, did they eat their accustomed Passover, for they were intent upon something else, but on the day after, which was the second of unleavened bread. But our Lord on the first day of unleavened bread, that is, on the fifth day of the week, kept the Passover with His disciples.