Numbers 9:9-12

And the Lord said to Moses, Say to the children of Israel, If any one of you or of your families is unclean because of a dead body, or is on a journey far away, still he is to keep the Passover to the Lord: In the second month, on the fourteenth day, in the evening, they are to keep it, taking it with unleavened bread and bitter-tasting plants; Nothing of it is to be kept till the morning, and no bone of it is to be broken: they are to keep it by the rules of the Passover.