A few passages from Karl Holl’s classic “The Distinctive Elements in Christianity” (1937) that will never lose their urgency:

dissolveJesus preaches a God who wants to have dealings with sinful men, a God to whom he who has sunk deep stands, in certain circumstances, especially near. And Jesus does not do this from undue consideration for weakness. His preaching begins with the proclamation of the Kingdom of God, which implies at the same an imminent ruthless judgment…

Jesus regards the will to forgiveness as rooted in God’s very innermost being.

He dealt a blow at everything that earnest ethical thinking about the relation between God and man had established, and everything that the common-sense understanding of mankind down to the present day has held to be the only right standard. It is all the more astonishing that on the basis of such a conception of God, which seemed to dissolve all morality, Jesus nevertheless built up an ethic, and the most exacting ethic conceivable at that…

This conception of God which Jesus taught, though it ran so sharply counter to all natural religious notions, still possessed its hidden, its irresistible strength. It went deeper than any other conception of God. For it spoke straight to the conscience. Was it not after all convincing that he who would aspire to fellowship with God must take his stand not on heroism, but unconditionally on God’s own moral nature, on God’s great goodness? For him who earnestly sought to do this, the distinction between the just and the unjust, the pure and the impure was dissolved… The admonition ‘know thyself’ now found its full significance.

Everything, then, pointed to one conclusion. He who grasped it was like a person awakening from a dream… that the ‘irrational’ made evident the actual truth, that what offended the commonsense of mankind, commended itself to the thoughtful as the revelation of a deeper and supremely convincing truth concerning God and man — herein lay the conquering power of Christianity.