Leviticus 19:18

לא תקם THOU SHALT NOT AVENGE — If one says to another “Lend me your sickle", and he replies, “No!", and the next day he (the latter) says to him (the former), “Lend me your hatchet”, and he retorts, “I am not going to lend it to you, just as you refused to lend me your sickle״ — this is avenging. And what is “bearing a grudge”? If one says to another, “Lend me your hatchet”, and he replies “No!” and on the next day he says to him “Lend me your sickle”, and he replies: “Here it is; I am not like you, because you would not lend me” — this is called “bearing a grudge (נטירה)” because he retains (נוטר) enmity in his heart although he does not actually avenge himself (Sifra, Kedoshim, Chapter 4 10-11; Yoma 23a). ואהבת לרעך כמוך THOU SHALT LOVE THY FELLOW MAN AS THYSELF —Rabbi Akiba said: “This is a fundamental principle of the Torah” (Sifra, Kedoshim, Chapter 4 12; Talmud Yerushalmi Nedarim 9:3).

לֹֽא־תִקֹּ֤ם וְלֹֽא־תִטֹּר֙ אֶת־בְּנֵ֣י עַמֶּ֔ךָ וְאָֽהַבְתָּ֥ לְרֵעֲךָ֖ כָּמ֑וֹךָ אֲנִ֖י יְהֹוָֽה׃

Thou shalt not avenge, nor bear any grudge against the children of thy people, but thou shalt love thy neighbour as thyself: I am the Lord.