(31) These are unclean.--Better, these are the most unclean, as Leviticus 11:29. That is, the eight animals thus enumerated are pre-eminently unclean of all the creeping things.

When they be dead.--The phrase, "whosoever doth touch them when they be dead," is simply another expression for "whosoever toucheth the carcase of them," which is used in Leviticus 11:24. Defilement is only contracted when their dead bodies are touched, but not if touched when alive. According to the canon which obtained during the second Temple, "there is no kind of living creature that becomes defiled while it is alive, or defiles when it is alive, save man only."

Verses 31-38. - As the little animals just mentioned - weasels, mice, and lizards - are more likely than those of a larger size to be found dead in domestic utensils and clothes, a further warning as to their defiling character is added, with talcs for daily use. The words translated ranges for pots (verse 35) should rather be rendered covered pots, that is, pots or kettles with lids to them. Seed which is to be sown, that is, seed corn, is not defiled by contact with these dead animals, unless it has been wetted by water being put on it, in which case the moisture would convey the corruption into the seeds.

11:1-47 What animals were clean and unclean. - These laws seem to have been intended, 1. As a test of the people's obedience, as Adam was forbidden to eat of the tree of knowledge; and to teach them self-denial, and the government of their appetites. 2. To keep the Israelites distinct from other nations. Many also of these forbidden animals were objects of superstition and idolatry to the heathen. 3. The people were taught to make distinctions between the holy and unholy in their companions and intimate connexions. 4. The law forbad, not only the eating of the unclean beasts, but the touching of them. Those who would be kept from any sin, must be careful to avoid all temptations to it, or coming near it. The exceptions are very minute, and all were designed to call forth constant care and exactness in their obedience; and to teach us to obey. Whilst we enjoy our Christian liberty, and are free from such burdensome observances, we must be careful not to abuse our liberty. For the Lord hath redeemed and called his people, that they may be holy, even as he is holy. We must come out, and be separate from the world; we must leave the company of the ungodly, and all needless connexions with those who are dead in sin; we must be zealous of good works devoted followers of God, and companions of his people.
]These are unclean to you of all that creep,.... Unfit for food, and not to be touched, at least when dead, as in the next clause, that is, these eight sorts of creeping things before mentioned, as the Targum of Jonathan expresses it, and these only, as Maimonides says (r):

whosoever doth touch them when they are dead shall be unclean until the even; for touching them while alive did not defile, only when dead; and this the Jews interpret, while they are in the case in which they died, that is, while they are moist; for, as Ben Gersom says, if they are so dry, as that they cannot return to their moisture, they do not defile; for which reason, neither the bones, nor nails, nor nerves, nor skin of these creeping things, defile; but, they say (s), while the back bone is whole, and the bones cleave to it, then a creeping thing is reckoned moist, and while it is so it defiles. (r) Hilchot, Abot Hatumaot, c. 4. sect. 14. (s) Maimon. & Bartenora in Misn. Niddah, c. 7. sect. 1.