“His chapters inspire me with more enthusiasm than even poetry itself. And the noble canon, with what true chivalrous feeling he confines his beautiful expressions of sorrow to the death of the gallant and high-bred knight, of whom it was a pity to see the fall, such was his loyalty to his king, pure faith to his religion, hardihood towards his enemy, and fidelity to his lady-love!”

Essay 1, Section 11
On the Genealogy of Morality (1887)
Context: To be incapable of taking one's enemies, one's accidents, even one's misdeeds seriously for very long—that is the sign of strong, full natures in whom there is an excess of the power to form, to mold, to recuperate and to forget[... ] Such a man shakes off with a single shrug many vermin that eat deep into others; here alone genuine 'love of one's enemies' is possible—supposing it to be possible at all on earth. How much reverence has a noble man for his enemies!—and such reverence is a bridge to love.—For he desires his enemy for himself, as his mark of distinction; he can endure no other enemy than one in whom there is nothing to despise and very much to honor!

Der Mensch der Erkenntniss muss nicht nur seine Feinde lieben, er muss auch seine Freunde hassen können.
Foreword, in the Oscar Levy authorized translation.
Variant translations:
The man of knowledge must be able not only to love his enemies but also to hate his friends.
Ecce Homo (1888)

Alcun non può saper da chi sia amato,
Quando felice in su la ruota siede:
Però c'ha i veri e i finti amici a lato,
Che mostran tutti una medesma fede.
Se poi si cangia in tristo il lieto stato,
Volta la turba adulatrice il piede;
E quel che di cor ama riman forte,
Ed ama il suo signor dopo la morte.
Canto XIX, stanza 1 (tr. B. Reynolds)
Orlando Furioso (1532)

Book I : "Concerning Discipline" Chapter 19 "The Duties of a King"
Arthashastra

Narrated Anas, in Bukhari, Volume 1, Book 2, Number 15
Sunni Hadith

Attributed to Cardinal Wolsey in English Etymology; Or, a Derivative Dictionary of the English Language (1783) by George William Lemon, "Alliteration".
Disputed

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 119.

So, the flowers of your field, in so far as I am gardener, shall come from my heart where they reside in much good will; and my eye and hand shall attend merely to the cultivating, the weeding, the fungous blight, the noxious insect of the air, and the harmful worm below.
And so shall your garden grow; from the rich soil of the humanities it will rise up and unfold in beauty in the pure air of the spirit.
So shall your thoughts take up the sap of strong and generous impulse, and grow and branch, and run and climb and spread, blooming and fruiting, each after its kind, each flowing toward the fulfillment of its normal and complete desire. Some will so grow as to hug the earth in modest beauty; others will rise, through sunshine and storm, through drought and winter's snows year after year, to tower in the sky; and the birds of the air will nest therein and bring forth their young.
Such is the garden of the heart: so oft neglected and despised when fallow.
Verily, there needs a gardener, and many gardens.
Source: Kindergarten Chats (1918), Ch. 4 : The Garden