'Unleavened Bread' in the Bible

It was now two days before the festival of the Passover and of Unleavened Bread. And the high priests and scribes were casting about for a way to arrest him by stealth and put him to death,

On the first day of the festival of Unleavened Bread, on which it was customary to kill the Passover lamb, Jesus' disciples said to him, "Where do you wish us to go and make the preparations for you to eat the Passover supper?"