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.
Letter of Aristeas
Letter of Aristeas to PhilocratesHim man must needs obey.' The king bestowed praise upon him and then asked another How he could maintain the truth? In reply to the question he said, 'By recognizing that a lie brings great disgrace upon all men, and more especially upon kings. For since they have the power to do whatever they wish, why should they resort to lies? In addition to this you must always remember, O King, that God is a lover of the truth.' The king received the answer with great delight and looking at another said, 'What is the teaching of wisdom?' And the other replied, 'As you wish that no evil should befall you, but to be a partaker of all good things, so you should act on the same principle towards your subjects and offenders, and you should mildly admonish the noble and good. For God draws all men to himself by his benignity.' The king praised him and asked the next in order How he could be the friend of men? And he replied, 'By observing that the human race increases and is born with much trouble and great suffering: wherefore you must not lightly punish or inflict torments upon them, since you know that the life of men is made up of pains and penalties. For if you understood everything you would be filled with pity, for God also is pitiful.'
Matthew 5:43
42 Give to the one who asks you, and do not reject the one who wants to borrow from you. 43 “You have heard that it was said, ‘Love your neighbor’ and ‘hate your enemy.’ 44 But I say to you, love your enemy and pray for those who persecute you, 45 so that you may be like your Father in heaven, since he causes the sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous.
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