This fulfilling of God’s law in loving others through the Spirit is rendered by faith, that is, by being satisfied with all that God is for us in Christ and him crucified—the perseverance of the same faith that justifies (Gal. 3:5; 5:6; 1 Tim. 1:5; Heb. 11:6, 24–26; 10:34).
Yes, it is rendered by faith and through faith, but it is critical to recall that the Hebrew word for “faith” and for “faithfulness” is emunah. One of the ways that the fulfillment of God’s law is rendered in us is by our obedience to it, in our walking.
…that the righteous requirement of the law might be fulfilled in us, who walk not according to the flesh, but according to the Spirit.
according to the Spirit, who is after all writing that very same law on our hearts.