Leviticus 15:12

The difference between the earthen and wooden vessel is the same as that in Leviticus 6:28; Leviticus 11:32 f. The rabbis inferred from this verse that metal vessels should be washed. The Jew who purchased a brasen pot was bound to wash it, for it might have been handled by one who was ritually unclean. These -washings of cups, and pots, and brasen vessels," are referred to in Mark 7:4.