102. Ruling in Front of One's Teacher
Talmud Torah 5:3
If a person asked a student to rule on a Torah matter and there were twelve mil (about 7.5 miles) between the student and his teacher, it is permitted for him to answer. In order to keep someone from performing a sin, it is permitted for a student to rule even in the presence of his teacher. This is the case when one sees someone doing something prohibited out of ignorance. In such a situation, one should try to prevent such things by informing the offender that the act in question is prohibited, even if he is in his teacher's presence and even though the teacher has not given him permission. Preventing a desecration of God's Name trumps giving deference to a teacher's honor.
This is only the case when a situation just happens to arise. It is forbidden to set oneself up as an authority in order to sit and answer all who ask regarding matters of law. This is so even if the student and the teacher are on opposite sides of the world. It is permitted if the teacher dies or gives his student permission to rule in matters of law. One is not automatically qualified to rule just because his teacher has died; one must also possess the necessary qualifications to do so.
Talmud Torah 5:4
Any student who is not qualified to rule in matters of law and does so anyway is foolish, evil and haughty. The verse “She has cast down many wounded” (Proverbs 7:26) applies to such a person. On the other hand, if a scholar is qualified to rule and refrains from doing so, he restrains the Torah and puts stumbling blocks before unwitting people. The latter part of that same verse, “many are those she has slain,” applies to him.
Lesser students who have not acquired sufficient Torah try to increase their prestige in the eyes of others by answering all questions of law in Israel. What they actually accomplish is creating conflict, destroying the world, extinguishing the light of Torah, and wrecking God’s metaphorical “vineyard.” Shir HaShirim references this by saying, “Take for us foxes, the little foxes that spoil the vineyards” (2:15).