Kindness is a behavior marked by ethical characteristics, a pleasant disposition, and concern for others. It is known as a virtue, and recognized as a value in many cultures and religions (see ethics in religion).
- According to Book Two of Aristotle's "Rhetoric" it is defined as virtue. It is defined as being "helpfulness towards someone in need, not in return for anything, nor for the advantage of the helper himself, but for that of the person helped".
- Philosopher Friedrich Nietzsche argued that kindness and love are the "most curative herbs and agents in human intercourse".
- Kindness is considered to be one of the Knightly Virtues.
- According to eighteenth century Bohemian philosopher Honza z Žižkova, kindness is the most important part of his practical philosophy on deceiving bureaucracy.
They also argue that, in a relationship, 'real kindness, real fellow-feeling, entails hating and being hated - that is, really feeling available frustrations – and through this coming to a more real relationship'.
- "Kindness is 'Pure Love' expressed / experienced / realized ~ 'Human Kindness' defines the fate of Humankind." Jaime Corpus Reyes, Waves Of Kindness Global Initiative 
- It has been suggested that 'most of Shakespeare's opus could be considered a study of human kindness'.
- Robert Louis Stevenson considered that 'the essence of love is kindness; and indeed it may best be defined as passionate kindness: kindness, so to speak, run mad and become importunate and violent'.
- The Christian apostle Paul lists kindness as one of the nine traits considered to be the "fruit of the Spirit"  in Galatians 5:22.
- Harvey, Peter (2007). An Introduction to Buddhism: Teachings, History and Practices. Cambridge: Cambridge University Press. ISBN 0-521-31333-3
- Warder, A. K. (1970; reprinted 2004). Indian Buddhism. Motilal Banarsidass: Delhi. ISBN 81-208-1741-9
- Gonda, J. (Ed.). (1977), A History of Indian Literature: Epics and Sanskrit religious literature, Medieval religious literature in Sanskrit (Vol. 2), Otto Harrassowitz Verlag; see page 62 and note 43
- Aristotle (translated by Lee Honeycutt). "Kindness". Rhetoric, book 2, chapter 7. Retrieved 2005-11-22.[dead link]
- Nietzsche, Friedrich Wilhelm. "On the History of Moral Feelings," Human, all too human: a book for free spirits. Aphorism 48. [Original: Menschliches, Allzumenschiles, 1878.] Trans. Marion Faber with Stephen Lehman. University of Nebraska Press: First Printing, Bison Books, 1996.
- Adam Phillips & Barbara Taylor, On Kindness (London 2009) p. 12
- Phillips, p. 94
- Lagrette Tallent Lenker, Fathers and Daughters in Shakespeare and Shaw (2001) p. 107
- robert Louis Stevenson, Virginibus Puerisque (London 1909) p. 35
- Galatians 5:22, New International Version
- RABBI-UL-AWWAL (July 1998). "What is Kindness to Parents?". Islamic Voice. 12-07 (139).
- El-Sayed M. Amin. "Kindness to a Non-Muslim Neighbor: Tips for Interaction". Society. Islam Online. Archived from the original on 2005-08-28. Retrieved 2005-11-22.