A.W. Tozer emphasizes the importance of engaging deeply with devotional literature, highlighting that many spiritual classics resonate across time and denominations, calling for genuine faith and a willingness to obey God's commandments. He warns that understanding these works requires participation in their truths, rather than mere intellectual pursuit, as true comprehension comes from living out the teachings. Tozer concludes that books should be viewed as tools for spiritual growth rather than ends in themselves, advocating for a thoughtful approach to reading that allows for true digestion of their messages.

The devotional works that have appeared have been so varied as to make classification difficult. Some of the great names are Meister Eckhart, Bernard of Clairvaux, Jan van Ruysbroeck, Michael Molinos, John of the Cross, Thomas Traherne, Richard Rolle, William Law, Walter Hilton, Francis de Sales, Jakob Boehme and Gerhart Tersteegen. To those might be added the more familiar names of Fenelon, Guyon and Thomas Kempis. To a large extent these were universal Christians who experienced the grace of God so deeply and so broadly that they encompassed the spiritual possibilities of all men and were able to set forth their religious experiences in language acceptable to Christians of various ages and varying doctrinal viewpoints. Just as a sincere hymn may strike a worshipful chord common to all Christians, so these works of devotion instantly commend themselves to true seekers everywhere. There need only be genuine faith in Christ, complete separation from the world, an eager cleaving unto God and a willingness to die to self and carry the cross, and the Holy Spirit will introduce His people to each other across the centuries and teach them the meaning of spiritual unity and the communion of saints. . . . . . . people are unable to appreciate the great spiritual classics because they are trying to understand them while having no intention to obey them. The Greek Church father, St. Gregory, said it better than I could, so we'll let him tell us: "He who seeks to understand commandments without fulfilling commandments, and to acquire such understanding through learning and reading, is like a man who takes shadows for truth. For the understanding of truth is given to those who have become participants in truth (who have tasted it through living). Those who are not participants in truth and are not initiated therein, when they seek this understanding, draw from it a distorted wisdom. Of such the apostle says, `The natural man receiveth not the things of the Spirit,' even though they boast of their knowledge of truth." In conclusion, we use books profitably when we see them as a means toward an end; we abase them when we think of them as ends in themselves. And for all books of every sort let us observe Bacon's famous rule: "Read not to contradict and confute, nor to believe and take for granted, nor to find talk and discourse, but to weigh and consider. Some books are to be tasted, others to be swallowed, and some few to be chewed and digested."