How do you know which person to befriend and who to stay away from? A person[’s character] is known through his anger. If he guards his holy neshamah when he is angered, if he does not allow it to be uprooteded [from him] and have a foreign spirit reside in its place, then this is a proper person. This is a perfect person, a true servant to His Master! (Zohar, parashas Tetzaveh, p. 182a)
