The nether or the upper millstone, used in their handmills; of which see Exodus 11:5 Numbers 11:8 Jeremiah 25:10. Under this one kind he understands all other things necessary to get a livelihood, the taking away whereof is against the laws both of charity and prudence, seeing by those things alone he can be enabled both to subsist and to pay his debts. A man's life, i.e. his livelihood, or the necessary supports of his life.
Related Commentaries of Deuteronomy 24:6
Deuteronomy 24:6
6 No man shall take the nether or the upper millstone to pledge: for he taketh a man's life to pledge.