9 I frankly avow to your Charity, before the Lord our God, whom I have taken, since the time when I began to serve Him, as a witness upon my soul, that as I have hardly found any men better than those who have done well in monasteries, so I have not found any men worse than monks who have fallen; whence I suppose that to them applies the word written in the Apocalypse, “He that is righteous, let him be still more righteous; and he that is filthy, let him be still more filthy.” Wherefore, if we be grieved by some foul blemishes, we are comforted by a much larger proportion of examples of an opposite kind. Let not, therefore, the dregs which offend your eyes cause you to hate the oil-presses whence the Lord's storehouses are supplied to their profit with a more brightly illuminating oil.
May the mercy of our Lord keep you in His peace, safe from all the snares of the enemy, my dearly beloved brethren.
Source: Letters (New Advent)