John Calvin's Commentary on the Bible - Exodus 12:15
Verse 15 15.Whosoever eateth leavened bread. This law specially refers to the keeping of the Passover. God had before forbidden the use of leaven; and He now enacts the punishment to be inflicted, if any should neglect the prohibition, and mingle leaven with the Paschal feast. But it is not without reason that we have postponed to this place what Moses has joined together with the institution of the Passover; for the plan proposed by us demands that the political laws, which sanction God’s... read more
Adam Clarke's Commentary on the Bible - 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... read more