Henry Mueller's Hours of Spiritual Refreshment was one of the most broadly used devotional texts in seventeenth century Lutheranism. Mueller writes in the tradition of Johann Gerhard and Johann Arndt, and other prominent devotional writers within the Lutheran tradition. Though his work is devotional, and his writings were influential among the early Pietists, Mueller writes with a profound sense of Lutheran Confessional theology. He promoted the rich devotional life which would characterize Pietism, while retaining orthodox theology. This work continues to profoundly affect the lives of those who read it, in pointing Christians to the love and grace of their Savior.