Provérbios 21:30 Halacá: Mishneh Torah, Testimony & Mishneh Torah, Torah Study

If the witness is a great sage and he is in a religious court which is his inferior in wisdom, because it is inconsistent with his honor [to appear before the court], the positive commandment of respect for the Torah takes precedence, and he may refrain from going. When are these matters said? For testimony about monetary issues. However, for testimony which prevents forbidden actions, and for testimony about capital matters or matters which could incur the punishment of lashes, he must go and testify, as it says (Berachot 19b), "There is neither wisdom nor understanding against the Lord."

If the distance between one and his master be twelve miles, and a man asked him a question, he is permitted to answer it. To separate one from committing a forbidden act, one may decide even in the presence of his master. For instance? Suppose he saw a man doing something which is really forbidden, because he did not know that it is forbidden, or because of his wickedness, he has authority to prevent him from doing it, and say to him: "This act is forbidden," even in the presence of his master, and even though his master did not give him the authority to act, for wherever there is a likelihood that the Name would be blasphemed, no honor is meted out to a master. Whereat are these words said? Only in matters which come to pass incidentally, but for one to establish himself for the purpose of rendering decisions, and to sit in a master's chair and render decisions to everyone who may ask of him, even though he be in one end of the world and his master be in the other end of the world, it is forbidden to do so prior to his master's demise, unless he obtained authority from his master. But not everyone whose master died may occupy a master's seat and teach the Torah, save if he be a disciple who attained judicial rank.³Sanhedrin, 5b; See Berakot, 63a and b. C. G.