הלכה אויף דברים 4:9

Even as man is obliged to instruct his son, so is he obliged to teach his son's son, for it is said: "But make them known to thy sons and thy sons' sons" (Ibid. 4.9); and, not alone to his son and his son's son, but each and every scholar in Israel is commanded to instruct all who desire to be his disciples, even though they be not his sons, for it is said: "And thou shalt teach them diligently unto thy children" (Ibid. 6.7.), which is traditionally interpreted²Sifre, Deut. 11. C. G. to include one's disciples; for disciples, too, are called children, as it is said: "And the sons of the prophets came forth" (Second Kings, 2.3.). If it be so, why then was one commanded to teach his son and his son's son? To permit the precedence of one's son to one's son's son, and his son's son to the son of his fellow.³Sukkah, 30b; Kiddushin, 30. G.

Until what age in life is one obliged to study the Torah? Even until the day of one's demise; for it is said: "And lest they depart from thy heart all the days of thy life" (Deut. 4.9.) Forsooth, as long as one will not occupy himself with study he forgets what he did study.¹⁰Kiddushin, 29b. G.

A person who is praying must not break off his prayer, except only if he is in mortal danger. Even when a king who is an Israelite greets him, he must not return the greeting. But if the king is an idolater, he stops, lest the king puts him to death. If, while standing and praying, he sees a king who is an idolater or a man of violence coming towards him, he should shorten the prayer. If unable to do so, he should stop praying. So too, if he sees snakes and scorpions, whose sting in that locality is deadly, moving in his direction, he stops his prayers as soon as they get near him and escapes. But if their sting is not deadly, he does not intermit his prayers.