Exodus 12:19

Verse Exodus 12:19. No leaven found in your houses] To meet the letter of this precept in the fullest manner possible, the Jews, on the eve of this festival, institute the most rigorous search through every part of their houses, not only removing all leavened bread, but sweeping every part clean, that no crumb of bread shall be left that had any leaven in it. And so strict were they in the observance of the letter of this law, that if even a mouse was seen to run across the floor with a crumb of bread in its mouth, they considered the whole house as polluted, and began their purification afresh. We have already seen that leaven was an emblem of sin, because it proceeded from corruption; and the putting away of this implied the turning to God with simplicity and uprightness of heart. See on Exodus 12:8, and Exodus 12:27, Exodus 12:27.