If a person refused to observe the required Passover, that person was to be cut off from the community. The Passover was a central act of worship that remembered God’s rescue of Israel from Egypt.
The phrase “cut off” can have more than one meaning in the Old Testament. It may refer to the death penalty. It may also mean banishment from the community (being removed from the people). The exact meaning in this case is not fully clear (see study note on Leviticus 7:20–21).