J. Gresham Machen was a Presbyterian of the Orthodox flavor in the late 19th and early 20th century. He is most well known for his little book, Christianity and Liberalism, as well as a founder of both the Orthodox Presbyterian Church and Westminster Theological Seminary in Philadelphia, PA.
Machen had a knack for concisely and clearly presenting and juxtaposing opposing viewpoints, namely Christianity and Liberalism.
Machen on the Christian Gospel:
Could anything be more impractical than the attempt to influence conduct by rehearsing events concerning the death of a religious teacher? That is what Paul called, “the foolishness of the message.” It seemed foolish to the ancient world, and it seems foolish to liberal preachers today. But the strange thing is it works.
Which this, as Machen, goes on to say is the problem with Liberalism, it’s unbelief and outright denial of the supernatural action of God in Christ. Liberalism tries to explain the Bible from a purely rational perspective.
Liberalism and Christianity is not too far off from what Martin Luther aptly defined as the Theologian of Glory and the Theologian of the Cross.
From the 95 theses, quoted in Luther on the Christian Life by Carl Trueman:
19. That person does not deserve to be called a theologian who looks upon the invisible things of God as though they were clearly perceptible in those things which have actually happened.
20. He deserves to be called a theologian, however, who comprehends the visible and manifest things of God seen through suffering and the cross.
21. A theologian of glory calls evil good and good evil. A theologian of the cross calls the thing what it actually is.
Precisely as Machen stated above, “strangely it works”. This is the power of the Gospel that the Liberal preachers deny and and on which the Christian preachers depend. The theologian of glory sees the cross void of power and death as defeat, whereas the theologian of the cross, sees it as it is, the Son of God veiled in human weakness to destroy death by dying. This message appears impractical, but “it is the power of God unto salvation for all who believe.” Romans 1:16