“As rain falls equally on the just and unjust, do not burden your heart with judgments but rain your kindness equally upon all.”

This is widely quoted as being from the Buddha. It seems to be an amalgamation of a quote from the New Testament and a loose paraphrase of the Lotus Sutra, which is a Mahayana scripture.

The first part is Matthew 5:44-45.

“But I say unto you, love your enemies, bless them that curse you, do good to them that hate you, and pray for them that despitefully use you and persecute you, that ye may be the children of your Father who is in Heaven. For He maketh His sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust.”

The rest sounds like a paraphrase from the “Lotus Sutra”:

“Know, Kashyapa! It is like unto a great cloud Rising above the world, Covering all things everywhere, A gracious cloud full of moisture; Lightning-flames flash and dazzle, Voice of thunder vibrates afar, Bringing joy and ease to all. The sun’s rays are veiled, And the earth is cooled; The cloud lowers and spreads As if it might be caught and gathered; Its rain everywhere equally Descends on all sides, Streaming and pouring unstinted, Permeating the land. On mountains, by rivers, in valleys, In hidden recesses, there grow The plants, trees, and herbs; Trees, both great and small, The shoots of the ripening grain, Grape vine and sugar cane. Fertilized are these by the rain And abundantly enriched; The dry ground is soaked, Herbs and trees flourish together. From the one water which Issued from that cloud, Plants, trees, thickets, forests, According to their need receive moisture. All the various trees, Lofty, medium, low, Each according to its size, Grows and develops Roots, stalks, branches, leaves, Blossoms and fruits in their brilliant colors; Wherever the one rain reaches, All become fresh and glossy. According as their bodies, forms And natures are great or small, So the enriching rain, Though it is one and the same, Yet makes each of them flourish.

“In like manner also the Buddha Appears here in the world, Like unto a great cloud Universally covering all things; And having appeared in the world, He, for the sake of the living, Discriminates and proclaims The truth in regard to all laws. The Great Holy World-honored One, Among the gods and men And among the other beings, Proclaims abroad this word: “I am the Tathagata, The Most Honored among men; I appear in the world Like unto this great cloud, To pour enrichment on all Parched living beings, To free them from their misery To attain the joy of peace, Joy of the present world, And joy of Nirvana….

“Upon all I ever look Everywhere impartially, Without distinction of persons, Or mind of love or hate. I have no predilections Nor any limitations; Ever to all beings I preach the Law equally; As I preach to one person, So I preach to all. Ever I proclaim the Law, Engaged in naught else; Going, coming, sitting, standing, Never am I weary of Pouring it copious on the world, Like the all-enriching rain. On honored and humble, high and low, Law-keepers and law-breakers, Those of perfect character, And those of imperfect, Orthodox and heterodox, Quick-witted and dull-witted, Equally I rain the Law-rain Unwearyingly.”

The idea of the Buddha of the Pali canon talking in terms of non-judgement is rather ludicrous. His emphasis was on terms of judging wisely rather than on not judging at all. For example here are Dhammapada verses 256-257:

To pass judgment hurriedly
doesn’t mean you’re a judge.
The wise one, weighing both
the right judgment & wrong,
judges others impartially —
unhurriedly, in line with the Dhamma,
guarding the Dhamma,
guarded by Dhamma,
intelligent:
he’s called a judge.