EXOD43 One must remember that it is extremely desirable to free oneself from the company of men whenever it is possible to do so and sit in his room alone, for most transgressions take place between two people--such as adultery, slander, lying, and flattery. He who sits alone will escape all these, for he will not vaunt himself over others and will not hear their scoffing. And when he is together with them, he must chastise them in three ways: in striking them, as in the case of Pinchas, who took a spear in his hand (Bemidbar 25:7); in word, as in the case of Moshe our teacher, may peace be upon him, who said to the wicked one [this verse]: "Why do you strike your friend?"; In thought, as in the case of King David, who said (Tehillim 26:5): "I hate the company of evil doers, and I will not sit with the wicked." And who can always contend with them, since they are always transgressing? But when you sit alone, you remove this responsibility from yourself and you are spared many transgressions. But one should befriend the saintly and the wise and sit in their company and learn from them, as it is written (Mishlei 13:20): "He who walks with the wise will become wise."