Unleavened Bread
The seven days after Passover, with no leaven in the house — the first of the three pilgrimage feasts.
The week from the fifteenth to the twenty-first of Nisan, kept with bread made without yeast because there was no time to let it rise. In practice it runs straight on from Passover and the two names are used for the same season — the gospels say "the feast of Unleavened Bread, which is called the Passover". Leaven had to be out of the house entirely, which is the image Paul reaches for when he tells a church to clear something out.
