ISB ~ James 2 v8

the royal law:The law of Christ’s kingdom (2:5), which incorporates the Mosaic laws of charity (2:8; Mt 22:34-40) and the commandments of the Decalogue (2:11; Mt 19:16-19) into the gospel teaching of Jesus (Mt 5-7; CCC 1972).

You shall love your neighbor:A citation from Lev 19:18.

• The precept of love is the summation of every commandment in the Torah dealing with our neighbor (Rom 13 :8-10). Beyond the quotation here, there are several allusions to Lev 19 throughout the Letter of James. This is clearest in the warnings against partiality (2:9; Lev 19:15), slander (4:11; Lev 19:16), withholding wages (5:4; Lev 19:13), and oath swearing (5:12; Lev 19:12).