'Pure' in the Bible

They are to set a leather-dyed skin covering over it, cover it with a pure blue cloth, and then insert its poles.

accompanied by one tenth of an ephah of fine flour for grain offering, mixed with one fourth of a hin of pure olive oil.

"Now you are to stay outside the camp for seven days, after which any of you who has killed a person or touched someone who was killed may purify yourselves on the third day. You and your captives will be pure on the seventh day.