The Epistle of James contains 108 verses in its five chapters.
In that brief space the author referred or alluded to Genesis, Exodus, Leviticus, Numbers, Deuteronomy, Joshua, 1 Kings, Job, Psalms, Proverbs, Ecclesiastes, Isaiah, Jeremiah, Ezekiel, Daniel, Hosea, Joel, Amos, Jonah, Micah, Zechariah, and Malachi.
This is nothing short of remarkable.
By doing this James obviated the need for any formal statement of inspiration; he merely assumed it, as most of the writers of Scripture did.
He did speak specifically of the authority of the Scriptures in 4:5–6 and had no hesitation about citing Scripture to prove his point.
Charles C. Ryrie, Biblical Theology of the New Testament (Dubuque, IA: ECS Ministries, 2005), 126.