19 For seven days no leaven is to be found in your houses.
The Israelites were not to eat any leaven for seven days. They were not to look at it. No one was allowed to have it in their houses. It was to be removed from them entirely.
See, leaven is the same thing as yeast. No yeast was to be found in their houses; they had to get it out.
Yeast is that substance we put in the dough that causes it to ferment and rise, making the bread light, airy, and puffed up. Paul uses puffed up as a metaphor for pride, something that the LORD hates.
See, leaven represents the sin, the junk, the rubbish in our lives. Malice. Pride. Backbiting. Sexual impurity. Hypocrisy. False teachings. We are commanded to correct it and get rid of it, not overlook or tolerate it. This is a command from the LORD.
Peace. Love. Go Forth and Clear It Out.