The website as a whole is addressed to practicing Christians but there's a lot of good material there completely suitable for an interfaith audience. Here's an example:
[Kindness] is as broad and old as humanity. The Greek playwright Sophocles alluded to the naturalness of kindness when he said, “Kindness gives birth to kindness.” The Roman emperor Marcus Aurelius understood the personal as well as the social benefits of kindness. “Ask thyself daily,” he wrote, “to how many ill-minded persons thou hast shown a kind disposition.” Goethe viewed kindness as the “golden chain by which society is bound together.” The fact that the word kindness is derived from the Old English gecynde, meaning natural, is a good indication that kindness is a very natural virtue. Shakespeare’s immortal and oft-quoted phrase, “the milk of human kindness” (Macbeth, act 1, scene 5), also attests to the naturalness of kindness, especially with regard to its manner of nourishment.As you may remember, the metta or loving-kindness meditation is simply based on the principle that first we wish ourselves happiness and well-being and then we extend that same wish to others.
In the contemporary world, we commonly hear reference to “random acts of kindness.” The expression was coined, presumably, to counteract “random acts of violence.” Nonetheless, acts of kindness are not fully themselves if they are random and impersonal. They should be well-placed and personal. “How truly is a kind heart a fountain of gladness,” wrote Washington Irving, “making everything in its vicinity to freshen into smiles.” No other virtue is better identified with the heart. Kindness and kindheartedness are synonymous, as are kind and kindhearted.
Small acts of watchful kindness are seldom performed in vain. And they have a marvelous proclivity for engendering successive acts of kindness. Moreover, kindness is versatile in its manner of expression. The kind look, gesture, or word can be as beneficial as the kind deed.
You know, it gives me a little lift just reading about it.