“A religious man is a person who holds God and man in one thought at one time, at all times, who suffers harm done to others, whose greatest passion is compassion, whose greatest strength is love and defiance of despair.”
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Abraham Joshua Heschel 130
Polish-American Conservative Judaism Rabbi 1907–1972Related quotes

Readings in Classical Chinese Philosophy (2001), p. 263
A similar phrase to the saying is found in the 3rd millennium BCE Sumerian text Instructions of Shuruppak by Šuruppak: "You should not serve things; things should serve you." http://etcsl.orinst.ox.ac.uk/section5/tr561.htm
"Cultivating oneself"

The Myth of Sisyphus (1942), Absurd Creation
Context: In that daily effort in which intelligence and passion mingle and delight each other, the absurd man discovers a discipline that will make up the greatest of his strengths. The required diligence and doggedness and lucidity thus resemble the conqueror's attitude. To create is likewise to give a shape to one's fate. For all these characters, their work defines them at least as much as it is defined by them. The actor taught us this: There is no frontier between being and appearing.

Riyadh-as-Saliheen by Imam Al-Nawawi, Hadith 376
Sunni Hadith
“There is only one who is all powerful, and his greatest weapon is love.”

Daedalus or Science and the Future (1923)

“Whose is the world? Whose is thought? His who loves them.”
Source: The Second Light (1986), p. 71