A Talmudic modification
Lo ba shamayim hee. This statement is often cited to indicate that the Torah that was revealed to the Israelites in the desert, was literally 'given' to them. It was in their hands and with it came the obligation to interpret it anew throughout the generations. There are very many examples in the Talmud of what appears to be a modification of the original text by our Sages.
One instance can be seen in the Talmud's discussion of the Ir haNidachat, a city that has been led to accept idol worship. We read in Deuteronomy 13, v.13-19 a seemingly clear set of instructions:
"If you hear in one of your cities that the Lord your G-d is giving you in which to live [a report] stating: 'lawless men have gone out from your midst and subverted the inhabitants of their city, saying "Let us worship the gods of others, [gods] that you have not known", you shall inquire, question and ask thoroughly, and behold, if the account is true and correct, the abomination was committed in your midst. You shall smite the inhabitants of that city by the sword, destroy it and everything that is in it, as well as its animals by the sword. And all its booty you shall gather in its square and you shall burn the city and all its booty in a fire, completely, to the Lord your G-d; and it shall remain an eternal heap, it shall never again be built".
The text calls to mind the instructions given to Saul to destroy Amalek. The fact that Saul did not carry out the instruction fully cost him his kingship (I Samuel, ch.15).
If we look at the discussion in Tractate Sanhedrin, ch.11 (Helek), we find an elaboration of what is involved in the case of the Ir ha Nidachat. The context is a consideration of various groups of people who have forfeited their share in the World to Come, the olam ha ba, such as, for example, the people of Sodom, the generation of the desert, of Korach and more. We are told that the people of Sodom deserved their fate, they sinned with their money, their bodies, they were arrogant, they stole, cheated and had unjust laws, - all sins between man and man. G-d metes out the punishment.
In the case of the sin of the Ir haNidachat, the sin is idol worship, a sin between man and G-d. The punishment is to be meted out by man ('you shall inquire,. smite...burn'). Unlike Sodom, which was an actual place, this was a potential city and, clearly, the Talmudic Sages were very wary of the responsibility for a wholesale destruction. The Mishna (San.111B) restricts the conditions: There must be at least two subverters, there must be a majority of idol worshipers in the city, they are not to be beheaded ('smitten by the sword') unless they belong to the city, each citizen – only men, since women are not mentioned in the text – must be accused by two witnesses and to have been warned beforehand; 'it shall never again be built' refers to structures, but, says R.Akiva, gardens and orchards may be created. The Gemara restricts matters even further: a town that has no 'square' (rehov, a public place) does not qualify, the property of righteous people is not to be burnt, - and more.
The Talmud here has considerably modified the instructions set out by Moses in Deuteronomy. The Torah was 'given' to us. The Talmudic modification was not arbitrary . The Talmudic Sages sought to understand the text in the context of the teachings of the entire Torah. Perhaps it was an attempt to take into account two of the Ten Commandments, 'Thou shalt not murder' and 'Thou shalt have no other gods besides Me'. The Oral Torah has its tradition of authority to give its interpretation of the text of the Written Torah.