Albert Schweitzer (14 January 1875 – 4 September 1965) was an Alsatian polymath. He was a theologian, organist, writer, humanitarian, philosopher, and physician. A Lutheran, Schweitzer challenged both the secular view of Jesus as depicted by the historical-critical method current at this time, as well as the traditional Christian view. His contributions to the interpretation of Pauline Christianity concern the role of Paul's mysticism of "being in Christ" as primary and the doctrine of Justification by Faith as secondary.
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You know of the disease called "sleeping sickness." There also exists a sleeping sickness of the soul. Its most dangerous aspect is that one is unaware of its coming. That is why you have to be careful. As soon as you notice the slightest sign of indifference, the moment you become aware of the loss of a certain seriousness, of longing, of enthusiasm and zest, take it as a warning. Your soul suffers if you live superficially.