Numbers 9:1-7

GOD spoke to Moses in the Wilderness of Sinai in the first month of the second year after leaving Egypt: “Have the People of Israel celebrate Passover at the set time. Celebrate it on schedule, on the evening of the fourteenth day of this month, following all the rules and procedures.” Moses told the People of Israel to celebrate the Passover and they did—in the Wilderness of Sinai at evening of the fourteenth day of the first month. The People of Israel did it all just as GOD had commanded Moses. But some of them couldn’t celebrate the Passover on the assigned day because they were ritually unclean on account of a corpse. So they presented themselves before Moses and Aaron on Passover and told Moses, “We have become ritually unclean because of a corpse, but why should we be barred from bringing GOD’s offering along with other Israelites on the day set for Passover?”