This feast was to last for 7 days. On the first and seventh day, there was to be a time of meeting between God and man. In the preparation for this meeting, all leaven products were to be removed from the household. This feast is recorded in Leviticus chapter 23:6–8.
It is not just spring housecleaning; it is to remind us of our need for spiritual cleansing and repentance. Combining this feast with Passover makes this an eight-day celebration. The one word that fits this feast is “Sanctification”. The Messiah was set apart. His body would not decay in the grave.