Leviticus 8:31

31.And Moses said unto Aaron and his sons, Boil the flesh This is the universal rule, as we have seen elsewhere. (411) One thing only is special, that God kept them in the tabernacle seven days, that they might learn to subordinate all their domestic cares and worldly business to their sacred duties. It has been elsewhere said, also, (412) that perfection is denoted by the number seven, which this passage confirms, for by the seven days they were reminded that they were no longer their own masters for the rest of their life.