Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The extends the principle to also prohibit the facilitation of a 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 to someone who has taken the 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.