The burning under the sentence of the Law took place after the death of the criminal by stoning, or strangling. Joshua 7:25.

They shall be burnt with fire - As there are worse crimes mentioned here, (see Leviticus 20:11 and Leviticus 20:17), where the delinquent is ordered simply to be put to death, or to be cut off, it is very likely that the crime mentioned in this verse was not punished by burning alive, but by some kind of branding, by which they were ever after rendered infamous. I need not add that the original, באש ישרפו baesh yishrephu, may, without violence to its grammatical meaning, be understood as above, though in other places it is certainly used to signify a consuming by fire. But the case in question requires some explanation; it is this: a man marries a wife, and afterward takes his mother-in-law or wife's mother to wife also: now for this offense the text says all three shall be burnt with fire, and this is understood as signifying that they shall be burnt alive. Now the first wife, we may safely presume, was completely innocent, and was legally married: for a man may take to wife the daughter if single, or the mother if a widow, and in neither of these cases can any blame attach to the man or the party he marries; the crime therefore lies in taking both. Either, therefore, they were all branded as infamous persons, and this certainly was severe enough in the case of the first wife; or the man and the woman taken last were burnt: but the text says, both he and they; therefore, we should seek for another interpretation of they shall be burnt with fire, than that which is commonly given. Branding with a hot iron would certainly accomplish every desirable end both for punishment and prevention of the crime; and because the Mosaic laws are so generally distinguished by humanity, it seems to be necessary to limit the meaning of the words as above.

And if a man take a wife, and her mother,.... Marry both the one and the other, or commit uncleanness with them, they consenting to it:

it is wickedness; abominable wickedness, shocking and detestable; there are other things, which also are wicked and not to be done, but this is extremely wicked, wickedness to a high degree:

they shall be burnt with fire, both he and they; the man, the mother and her daughter both being married together to him, or both consenting to his lying with them; otherwise, if one of them was first his wife, it was not reasonable that she should be put to death; and therefore some interpret "they", one of them, as Jarchi observes, one or other of them; and so Aben Ezra explains it, this or that; if the mother was his wife, the daughter was to be burnt; and so on the contrary, if the daughter was his wife, the mother was to be burnt; according to the Targum of Jonathan, they were to be burnt by pouring lead into their mouths: and so the manner of burning is described in the Misnah (g); they that are to be burnt are fixed in dung up to their knees, then they put a hard napkin within a soft one, and roll it about is neck; one draws it one way, and another another way, until he opens his mouth; then they take hot melted lead, and pour it into his mouth, which goes down into his bowels and burns them. But it was rather done with faggots, of which an instance is given:

that there be no wickedness among you; of such kind, continued, countenanced, and pass unpunished. This punishment was to be inflicted, to deter persons from it. The law against it is in Leviticus 18:17.

(g) Sanhedrin, c. 7. sect. 2.

And if a man take a wife and her mother, {f} it is wickedness: they shall be burnt with fire, both he and they; that there be no wickedness among you.

(f) It is an abominable and detestable thing.

20:14 They - All who consented to it.

20:10-27 These verses repeat what had been said before, but it was needful there should be line upon line. What praises we owe to God that he has taught the evil of sin, and the sure way of deliverance from it! May we have grace to adorn the doctrine of God our Saviour in all things; may we have no fellowship with unfruitful works of darkness, but reprove them.