“Spiritual progress is like a detoxification.”

The Size of the Soul, p. 22

Source: The Sayings and Teachings of the Great Mystics of Islam (2004), p. 95

Source: Something More, A Consideration of the Vast, Undeveloped Resources of Life (1920), p. 58
Context: It is utterly impossible to measure the influence of Jesus upon the moral and spiritual progress of the world. The greater value put on human life, the more honored place of womanhood, the nobler attitude toward childhood, the abolition of many giant evils, are founded upon the spirit and teaching of Jesus. Our new world-ideal of democracy and human brotherhood is a direct outgrowth of his example and teaching. Much has been accomplished. Much more is still to be done.

Source: The Sayings and Teachings of the Great Mystics of Islam (2004), p. 82

Book 3, Chapter 8 (p. 301)
Lord Valentine's Castle (1980)

Interview in The Voice of Ethiopia (5 April 1948).
Context: The progress of science can be said to be harmful to religion only in so far as it is used for evil aims and not because it claims a priority over religion in its revelation to man. It is important that spiritual advancement must keep pace with material advancement. When this comes to be realized man's journey toward higher and more lasting values will show more marked progress while the evil in him recedes into the background. Knowing that material and spiritual progress are essential to man, we must ceaselessly work for the equal attainment of both. Only then shall we be able to acquire that absolute inner calm so necessary to our well-being.
It is only when a people strike an even balance between scientific progress and spiritual and moral advancement that it can be said to possess a wholly perfect and complete personality and not a lopsided one.

University Graduation address (2 July 1963), published in Important Utterances of H. I. M. Emperor Haile Selassie I, 1963-1972 (1972), p. 22.
Context: Education is a means of sharpening the mind of man both spiritually and intellectually. It is a two-edged sword that can be used either for the progress of mankind or for its destruction. That is why it has been Our constant desire and endeavor to develop our education for the benefit of mankind.
A qualified man with vision, unmoved by daily selfish interests, will be led to right decisions by his conscience. In general, a man who knows from whence he comes and where he is going will co-operate with his fellow human beings. He will not be satisfied with merely doing his ordinary duties but will inspire others by his good example. You are being watched by the nation and you should realize that you will satisfy it if you do good; but if, on the contrary, you do evil, it will lose its hope and its confidence in you.

Everest Aspiration (1977)