“To be a follower of the Crucified means, sooner or later, a personal encounter with the cross. And the cross always entails loss. The great symbol of Christianity means sacrifice and no one who calls himself a Christian can evade this stark fact.”

Paris Review interview (1958)
Context: No one is without Christianity, if we agree on what we mean by that word. It is every individual’s individual code of behavior by means of which he makes himself a better human being than his nature wants to be, if he followed his nature only. Whatever its symbol — cross or crescent or whatever — that symbol is man’s reminder of his duty inside the human race. Its various allegories are the charts against which he measures himself and learns to know what he is. It cannot teach a man to be good as the textbook teaches him mathematics. It shows him how to discover himself, evolve for himself a moral codes and standard within his capacities and aspirations, by giving him a matchless example of suffering and sacrifice and the promise of hope.

Meditations. Yogas, Gods, Religions (2000)

Source: Unless You Become Like This Child

Source: Discipleship (1937), Discipleship and the Cross, p. 86

This has commonly been paraphrased: The last Christian died on the cross.
Sec. 39
The Antichrist (1888)

Source: Discipleship (1937), Discipleship and the Cross, p. 88

Source: Quotes from secondary sources, Dictionary of Burning Words of Brilliant Writers, 1895, P. 171.

Did Adam have a Bellybutton?: And other tough questions about the Bible (2000)