Halakhah su Salmi 7:5

Whoever takes revenge on someone, violates a negative commandment, for it is written, "Do not take revenge."²⁶Leviticus 19:18. And what constitutes vengeance? Reuvein says to Shimon, "Lend me your spade!"²⁷The prohibition against vengeance is not limited to the loaning of tangible articles, it also includes requests for monetary loans, favors or charity. (Mishnah Berurah 156:4) [Shimon] replies, "No, I will not lend it to you." The next day [Shimon] has to borrow something and he says [to Reuvein]: "Lend me your spade." [Reuvein] says: "No, I will not lend it to you, just as you did not lend me [yours] when I asked you for it." This constitutes taking revenge, and he [Reuvein] has violated a negative commandment. Rather when [Shimon] comes to borrow something, he should give it to him wholeheartedly and not pay him back for what he did to him. It is becoming for a person to show forebearance in all mundane matters, for in the eyes of understanding people, they are all nothing but vanity and futility, and not worth taking revenge because of them. And thus said King David, peace be upon him,²⁸Psalms 7:5. "If I have repaid my friends with evil,²⁹The meaning of this passage becomes clear when it is read in conjuction with the next verse, “If I have repaid others with evil—then let the enemy pursue my soul.” I who released my unprovoked adversary. (For the prohibition against uttering curses, see Chapter 6: 3).