“Purity of heart is love for the weak who constantly fall.”

"Emperor's Soundtrack"
Albums, Lupe Fiasco's Food & Liquor (2006)

Source: The Wild (1995), p. 388

Source: Anna Karenina

Original: Prenditi costantemente cura di chi porti nel tuo cuore.
Source: prevale.net

Source: A Return to Love: Reflections on the Principles of "A Course in Miracles" (1992), Ch. 7 : Work, §9 : Sales to Service
Context: Purity of heart will not make us poor. The exaltation of poverty as a spiritual virtue is of the ego, not the spirit. A person acting from a motivation of contribution and service rises to such a level of moral authority, that worldly success is a natural result.
Give all your gifts away in service to the world. If you want to paint, don’t wait for a grant. Paint a wall in your town that looks drab and uninviting. You never know who’s going to see that wall. Whatever it is you want to do, give it away in service to your community.

"The Black Boy Looks at the White Boy" in Esquire (May 1961)
Variant: Nobody is more dangerous than he who imagines himself pure in heart; for his purity, by definition, is unassailable.
Source: Nobody Knows My Name

" The Buried Life http://www.victorianweb.org/authors/arnold/writings/buriedlife.html" (1852), st. 2
Context: Alas! is even love too weak
To unlock the heart, and let it speak?
Are even lovers powerless to reveal
To one another what indeed they feel?
I knew the mass of men conceal'd
Their thoughts, for fear that if reveal'd
They would by other men be met
With blank indifference, or with blame reproved;
I knew they lived and moved
Trick'd in disguises, alien to the rest
Of men, and alien to themselves — and yet
The same heart beats in every human breast!

Original: La persona che cattura costantemente la tua attenzione domina: istinto, cuore, umore e ragione.
Source: prevale.net