Lifnei Iver - in Jewish Oral Law

In Jewish Oral Law

Many halakhic principles are derived from lifnei iver, the oral Torah expanding its ramifications beyond a purely literal interpretation. In classical rabbinical literature, lifnei iver is seen as a figuratively expressed prohibition against misleading people; the Sifra (a midrash from the time of the Mishnah) argues that since the recipient of advice would be metaphorically blind in regard to its accuracy, they would metaphorically stumble if the advice was damaging or otherwise bad.

The Talmud extends the principle to also prohibit the facilitation of a sinful act by another individual, where the person in question would otherwise have lacked the opportunity or means to have committed the sin; for example, the Talmud takes the regulation to prohibit the giving of a cup of wine to someone who has taken the nazirite vow (which includes a vow to not partake in wine or grape products). The Talmud expresses caution in regard to figurative interpretations of this principle, emphasising that the law only really covers those situations where the other individual could not possibly have committed the transgression without the aid of the first person violating the lifnei iver rule; this is known in the Talmud as two sides to the river (Trei Ivrah deNaharah) - if, for example, the person who took a nazirite vow had been about to take a glass of wine anyway, then handing them a glass of wine would not transgress lifnei iver.

Lifnei iver as a principle recurs many times in more practical applications of Jewish law. For example, the Shulchan Aruch, which traditional Judaism views as authoritative, warns a father to not physically chastise older children, as this will only entice them to hit back, which in its view would be a capital offence (Shulchan Aruch Yoreh Deah 240:20).