Penned by Dr. Martin Luther in 1535:
Next to Holy Scripture there certainly is no more useful book for Christendom than that of the lives of the saints, especially when unadulterated and authentic. For in these stories one is greatly pleased to find how they sincerely believed God’s Word, confessed it with their lips, praised it by their living, and honored and confirmed it by their suffering and dying. All this immeasurably comforts and strengthens those weak in the faith and increases the courage and confidence of those already strong far more than the teaching of Scripture alone, without any examples and stories of the saints. Although the Spirit performs His work abundantly within, it nonetheless helps very much to see or to hear the examples of others without. Otherwise a weak heart always thinks: See, you are the only one who so believes and confesses, acts, and suffers. For this reason God Himself in Scripture also describes the life, faith, confession, and suffering of the dear patriarchs and prophets along with their doctrine, and St. Peter, too, comforts Christians with the examples of all the saints and says: “Know that the same afflictions are accomplished in your brethren that are in the world” (1 Peter 5:9).
Quoted from What Luther Says, p. 1251.