He prohibited us from sexual intercourse with the wife of the son. And that is His, may He be exalted, saying, "The nakedness of your daughter-in-law you shall not uncover" (Leviticus 18:15). And one who transgresses this negative commandment is [punished] by stoning. But if the testimony was not ratified or it was not known, it is with excision if it was volitional. However if he was inadvertent, he must sacrifice a fixed sin-offering.