TSK
Treasury of Scripture Knowledge references in NET.
For seven days you must eat bread made without yeast. Surely on the first day you must put away yeast from your houses because anyone who eats bread made with yeast from the first day to the seventh day will be cut off from Israel.
“When a resident foreigner lives with you and wants to observe the Passover to the LORD, all his males must be circumcised, and then he may approach and observe it, and he will be like one who is born in the land– but no uncircumcised person may eat of it.
Whoever makes perfume like it and whoever puts any of it on someone not a priest will be cut off from his people.’”
But the man who is ceremonially clean, and was not on a journey, and fails to keep the Passover, that person must be cut off from his people. Because he did not bring the LORD’s offering at its appointed time, that man must bear his sin.
Clean out the old yeast so that you may be a new batch of dough– you are, in fact, without yeast. For Christ, our Passover lamb, has been sacrificed.