Augustine on Mean Friends and Nice Enemies

Not every one who is indulgent is a friend; nor is every one an enemy who smites. Better are the wounds of a friend than the proffered kisses of an enemy. It is better with severity to love, than with gentleness to deceive. More good is done by taking away food from one who is hungry, if, through freedom from care as to his food, he is forgetful of righteousness, than by providing bread for one who is hungry, in order that, being thereby bribed, he may consent to unrighteousness. He who binds the man who is in a phrenzy, and he who stirs up the man who is in a lethargy, are alike vexatious to both, and are in both cases alike prompted by love for the patient.

Who can love us more than God does? And yet He not only give us sweet instruction, but also quickens us by salutary fear, and this unceasingly. Often adding to the soothing remedies by which He comforts men the sharp medicine of tribulation, He afflicts with famine even the pious and devout patriarchs, disquiets a rebellious people by more severe chastisements, and refuses, though thrice besought, to take away the thorn in the flesh of the apostle, that He may make His strength perfect in weakness. Let us by all means love even our enemies, for this is right, and God commands us so to do, in order that we may be the children of our Father who is in heaven, "who maketh His sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust." But as we praise these His gifts, lets us in like manner ponder His correction of those whom He loves.
St. Augustine of Hippo, Epistle 93