Leviticus 11:34

That on which such water cometh That flesh, or herbs, or other food which is dressed in water, in a vessel so polluted, shall be unclean: not so, if it be food which is eaten dry, as bread, or fruits; the reason of which difference seems to be this, that the water did sooner receive the pollution in itself, and convey it to the food so dressed. All this was intended to teach them to avoid carefully every thing that was polluted in their common actions. Not only the vessels of the sanctuary, but every pot in Jerusalem and Judah must be holiness to the Lord, Zechariah 14:20. The laws in these cases were very critical, and the observance of them would be difficult, and the exceptions also were very nice: but it was all designed to exercise them to a constant care and exactness in their obedience. And we, who by Christ are delivered from these burdensome observances, are hereby taught not to be less circumspect in the more weighty matters of the law. We ought as industriously to preserve our precious souls from the pollutions of sin, and as speedily to cleanse them when they are polluted, as they were to preserve and cleanse their bodies and household goods from these ceremonial pollutions.