For the original recipients, to “do justice” was at the very least a call to act in such a way as to reverse all the evil taking place. It meant doing justly in accord with the will and purpose of God as He had manifested it and revealed it to them in Scripture.
For example, in Deuteronomy 10:18, Moses says that God “executes justice for the fatherless and the widow, and loves the sojourner, giving him food and clothing.” So within the framework of God’s revelation of Himself, we want to take these things seriously—perhaps far more seriously than we have to this point in our lives. Surely James had Deuteronomy in mind when he wrote, “Religion that is pure and undefiled before God the Father is this: to visit orphans and widows in their affliction, and to keep oneself unstained from the world” (James 1:27).
In short, we might say that this command to “do justice” is the inevitable fulfillment of our Lord’s command to love our neighbors as we love ourselves (Matt. 22:39; Mark 12:31; Luke 10:27; see also Lev. 19:18; Matt. 19:19; Rom. 13:9; Gal. 5:14; James 2:8).
This article has been adapted from the sermon “What God Requires” by Alistair Begg.