They are two inseparable though distinct sides of one and the same reality. When these sides form one whole in the man being saved, faith has primacy and comes first, as the cause. Works follow as its effect.
But why does one Apostle speak chiefly about the importance of works, namely James, while the other speaks about the importance of faith, namely Paul?
Because the disciples of one Apostle, those of James, directed their attention more and more to one side, faith in Jesus, while neglecting the other, works.
The disciples of the other Apostle, those of Paul, were being drawn by false teachers in the opposite direction. They were drawn toward the works of the Old Testament law, and away from the first side, faith in Jesus.
Therefore each Apostle wished to explain to his disciples the importance of precisely that side of the matter which they had neglected, or at least had left without proper attention.
To the Judaizing Christians of the dispersion, who carelessly dreamed of being saved by the high rights of Christianity alone, proudly claimed for themselves, the holy Apostle James had special reason to explain the importance of moral works.
He also had reason to explain the necessity of labors, according to one's strength, for self-purification from sinful defilement.
To Christians converted from paganism, upon whom some wished to impose Jewish ritual and law, the Apostle to the nations, Saint Paul, had special reason to explain the decisive importance of faith in Jesus for justification.
He explained its superiority over the works of the Jewish ritual law, which are already superfluous in Christianity. He also explained its superiority over the works of the moral law in general, of which man does not possess enough for justification.
Apart from the concepts and disposition of their disciples, the holy Apostles James and Paul held exactly the same view of faith and works.
For if the holy Apostle James lowers faith before works, he lowers only that faith which even the demons have and tremble. That is, he means only an abstract, intellectual, cold, and superficial faith (Jas 2:19).
This, therefore, is not Paul's faith at all.
Conversely, if the holy Apostle Paul exalts faith before works, he does not mean the faith which the Apostle James lowers. He means faith working through love (Gal 5:6).
In other words, he means faith accompanied by works of Christian love. This is precisely the thing for which the holy Apostle James contends.
For what works does the holy Apostle James consider necessary for salvation? He names this: "to visit orphans and widows in their affliction, and to keep oneself unstained from the world" (Jas 1:27).
He also names works like the deeds of Abraham and Rahab (Jas 2:21-25). These are works of mercy toward neighbors and unquestioning obedience to God.
And what works does the holy Apostle Paul declare indifferent and unnecessary for salvation? The works of the ritual law of the Old Testament.
"For in Christ Jesus neither circumcision nor uncircumcision avails anything" (Gal 5:6).
As for the moral duties of active piety, the strongest passages on their importance and necessity are found precisely in the Apostle Paul, for example Rom 6:1, 2, 7, 11, 18.
Yet Saint Paul still ascribes decisive force and significance in justification to faith, not to works. This is not because he denies the need for works in justification.
On the contrary, it is because even the most pious man does not possess as many righteous works as would be needed for his justification.
Rather, we are all sinners by our fallen nature. All our moral deficiencies are filled up only by the merits of Christ.
These merits are imputed and appropriated to us through faith, and they impart value also to our own good works.