Jamieson, Fausset and Brown on Galatians 5:14

14. all the law--Greek, "the whole law," namely, the Mosaic law. Love to God is presupposed as the root from which love to our neighbor springs; and it is in this tense the latter precept (so "word" means here) is said to be the fulfilling of "all the law" (Le 19:18). Love is "the law of Christ" (Ga 6:2; Mt 7:12; 22:39, 40; Ro 13:9, 10).

is fulfilled--Not as received text "is being fulfilled," but as the oldest manuscripts read, "has been fulfilled"; and so "receives its full perfection," as rudimentary teachings are fulfilled by the more perfect doctrine. The law only united Israelites together: the Gospel unites all men, and that in relation to God [Grotius].