Leviticus 19:18
17 You must not hate your brother in your heart. You must surely reprove your fellow citizen so that you do not incur sin on account of him. 18 You must not take vengeance or bear a grudge against any of your people, but you must love your neighbor as yourself. I am the Lord. 19 You must keep my statutes. You must not allow two different kinds of your animals to breed together, you must not sow your field with two different kinds of seed, and you must not wear a garment made of two different kinds of material.
Mark 12:31
30 Love the Lord your God with all your heart, with all your soul, with all your mind, and with all your strength.’ 31 The second is: ‘Love your neighbor as yourself.’ There is no other commandment greater than these.” 32 The expert in the law said to him, “That is true, Teacher; you are right to say that he is one, and there is no one else besides him.
Pirkei Avot 2:10
Mishnah10 They [each] said three things: Rabbi Eliezer said: Let the honor of your friend be as dear to you as your own; And be not easily provoked to anger; And repent one day before your death. And [he also said:] warm yourself before the fire of the wise, but beware of being singed by their glowing coals, for their bite is the bite of a fox, and their sting is the sting of a scorpion, and their hiss is the hiss of a serpent, and all their words are like coals of fire. 11 Rabbi Joshua said: an evil eye, the evil inclination, and hatred for humankind put a person out of the world. 12 Rabbi Yose said: Let the property of your fellow be as precious unto you as your own; Make yourself fit to study Torah for it will not be yours by inheritance; And let all your actions be for [the sake of] the name of heaven.
Notes and References
"... Despite the fact that the book of Leviticus is not frequently quoted among those from the Pentateuch by Mark, Matthew and the Lukan writings, at least one clear allusion and five explicit quotations from Leviticus are to be found in the Synoptic Gospels and the Acts of the Apostles ... in the early second century CE, Rabbi Akiba “spoke of the same passage (Leviticus 19:18) as ‘the greatest general principle in the Torah’” (see Genesis Rabbah 24:7 and Sifra on Leviticus 19:18). Other pre-Christian Jewish sources which also include the summary of the law, are to be found in “Tobit 4:15 (compare Sirach 31:15), Letter of Aristeas 207-208 (with the positive also indicated), and the Jerusalem Targum of Leviticus 19:18.” Despite being rare, the positive form can also be found in pre-Christian Jewish literature (Letter of Aristeas 20; 2 Enoch 61:2; Pirkei Avot 2.10, 12) ... Some interesting intertextual connections regarding Leviticus 19:18 can also be found in both the Testament of Dan, as well as in the Testament of Issachar. But it is especially Leviticus 19:18 which displays a broad early Christian trajectory, covering the Pauline and Gospel traditions, the Western text, Acts 15:20 and 15:28, as well as the Didache (Didache 1:2), the early Church Fathers (Barnabas 19.5; Justin Martyr, Dialogue 93.2) and the Coptic Gospel of Thomas 6. It is no surprise that the New Testament writers frequently quote the so-called “golden rule”, or “rule of reciprocity” from Leviticus 19:18. They probably traced the origins of the “golden rule” back to a Logion in the Jesus-tradition which contained Jesus’ own summary of the law ..."
Steyn, Gert J. "The Text Form of the Leviticus Quotations in the Synoptic Gospels and the Acts of the Apostles" in Himbaza, Innocent (ed.) The Text of Leviticus: Proceedings of the Third International Colloquium of the Dominique Barthélemy Institute (pp. 205-242) Peeters, 2020