Love your neighbor as yourself (19:18). Such an attitude is illustrated by the covenanted love between David and Jonathan, who loved him “as he loved his own life” (1 Sam. 18:3, etc.). Similar loyal love is described in a treaty between the Hittite king Tudḫaliya IV and Kurunta of Tarḫuntašša. Leviticus 19:34 extends the command to love as oneself to the resident alien, who is to be treated like a native citizen. Similarly, a Mesopotamian treaty text from Alalakh provides that “[if people of my land] enter your land to preserve themselves from starvation, you must protect them and you must feed them like (citizens of) your land.”

13:8–10 Love and the law

The first part of v 8 is transitional. Let no debt remain outstanding repeats an important implication drawn from the need for Christians to submit to secular rulers (cf. v 7a) and is the basis for Paul’s reminder that Christians owe one debt that they can never repay: the continuing debt to love one another. Paul returns to the theme of love (see 12:9–21), highlighting its importance by presenting it as the fulfilment (8b and 10), or summary (9), of the Mosaic law. The centrality of Lv. 19:18, the ‘love command’, was stressed by Jesus himself (Mt. 5:43; 19:19; 22:39; Mk. 12:31; cf. Jn. 13:34–35), and is echoed throughout the NT (cf. Gal. 5:14; Jas. 2:8; 4:11–12; 1 Jn. 4:11, passim). What Paul means when he insists that obedience to this commandment ‘fulfils’ or ‘sums up’ all the other commandments is not the idea that all we need to do to please God is to ‘love’—with the implication that as long as we have a ‘loving’ feeling, we can do anything else we please. Nor does Paul mean that loving others is simply the most important commandment in the law, or the spirit in which all the others are to be obeyed. Rather, he is saying that Christians now fulfil all the demands of the Mosaic law (at least those that relate to our obligations to other people) by loving. For love is at the heart of the ‘law of Christ’ (Gal. 6:2 cf. 1 Cor. 9:20–21), the law that Jesus made regulative of life in the new realm in which we live. And this law itself ‘fulfils’ the Mosaic law (see Mt. 5:17).

12 The word "therefore" probably refers to the entire body of the sermon (5:17-7:12), for here there is a second reference to "the Law and the Prophets" (see comment on 5:17); Jesus stresses that he has taught about the true direction in which the OT law points, i.e., the Golden Rule. This rule sums up the Law and the Prophets (cf. Ro 13:9). In the context of fulfilling the Scriptures, it provides a handy summary of the righteousness to be displayed in the kingdom (cf. 5:20).

The verb translated "sums up" (lit., "is") might properly be translated "fulfills," as in Ac 2:16. In the deepest sense, therefore, the rule is the Law and the Prophets in the same way as the kingdom is the fulfillment of all that the Law and the Prophets foretold.