Ex 12.6-18 And ye shall keep it up until the fourteenth day of the same month: and the whole assembly of the congregation of Israel shall kill it in the evening.
2Cron 29.34 But the priests were too few, so that they could not flay all the burnt offerings: wherefore their brethren the Levites did help them, till the work was ended, and until the other priests had sanctified themselves: for the Levites were more upright in heart to sanctify themselves than the priests.