James 2:8

μέντοι, rare in N.T.; 5 times in St John; also 2 Timothy 2:19; Jude 1:8. It introduces a concession. If however ye fulfil the royal law (which you transgressed by dishonouring the poor through προσωπολημψία) ye do well.

νόμον … βασιλικόν. The position of βασιλικόν is emphatic, and distinguishes the law of Christ, the βασιλεύς, from the Mosaic law. Compare Plato, Ep. p. 1297 Α εἰς βασιλέως δʼ εἶδος πειρᾶσθαι μεταβάλλειν καὶ δουλεῦσαι νόμοις βασιλικοῖς, and 2Ma 3:13 διʼ ἃς εἶχε βασιλικὰς ἐντολάς, i.e. the laws or commands which a king makes and issues, the meaning here and not, as has been suggested, ‘the law which even kings obey.’ The expression does not occur elsewhere in the N.T., but it is natural that the thought of the βασιλεία, the kingdom, or, as it would mean to a contemporary, the empire of Christ, should be especially present with the Apostle, who was himself of the royal line of David. It is a phrase which bears upon it the stamp of an original writer summing up a leading point of Christian teaching, and not by any means one likely to have been invented by a late writer.

ἀγαπήσεις τὸν πλησίον σου ὡς σεαυτόν. See Leviticus 19:18, and Matthew 19:19, and comp. Romans 13:9 τὸ γὰρ οὐ μοιχεύσεις …, καὶ εἴ τις ἑτέρα ἐντολή, ἐν τῷ λόγῳ τούτῳ ἁνακεφαλαιοῦται, ἐν τῷ Ἀγαπήσεις τὸν πλησίον σου ὡς σεαυτόν κ.τ.λ.

καλῶς ποιεῖτε, ye do well, i.e. you are right, comp. Aristoph. Plut. 859 καλῶς τοίνυν ποιῶν�. So, “Di bene fecerunt inopis me quodque pusilli │ finxerunt animi,” Hor. Sat. I. 4. 17. See also Acts 15:29 ἐξ ὧν διατηροῦντες ἑαυτοὺς εὖ πράξετε.