Laudator Temporis Acti

Augustine, Sermons 254.2 (Patrologia Latina, vol. 38, col. 1182; tr. Edmund Hill):

Sadness, you see, is just like dung. Dung dumped in what isn't its proper place is filth; dung dumped in what isn't its place makes a house filthy; dumped in its proper place it makes a field fertile.

Tristitia enim sic est, quomodo stercus. Stercus non loco suo positum immunditia est. Stercus non loco suo positum immundam facit domum; loco suo positum fertilem facit agrum.

Id. 254.5 (Patrologia Latina, vol. 38, col. 1184):

So it's a foul, an ugly time, but let it be the ugliness of dung in the field, not in the house. Let the sorrow be for sins, not for greedy desires cheated and disappointed. It's a foul, ugly time, but if used well a fertile time. What could be more foul than a field spread with farmyard muck? The field was beautiful before it received its cartload of muck from the dunghill. The field was first reduced to ugliness, in order to attain to fruitfulness. So the ugliness of this time is a sign, but let this ugliness be for us a time of fertility.

Ideo foedum tempus, sed foeditas ista stercoris sit in agro, non in domo. Maeror sit de peccatis, non de cupiditatibus fraudatis. Foedum tempus, sed, si bene utatur, fertile tempus. Quid foedius agro stercorato? Pulcher fuit ager, antequam cophinum haberet stercoris. Perductus est prius ager ad foeditatem, ut veniret ad ubertatem. Foeditas ergo huius temporis signum est, sed nobis sit ista foeditas tempus fertilitatis.

See Pierre Charles, "L'élément populaire dans les sermons de saint Augustin," Nouvelle Revue Théologique 69.6 (1947) 619-650 (at 629).