Dead flies cause the ointment of the perfumer to send forth a foul odor: so does a little folly to him that is respected for wisdom and honor.
All Commentaries on Ecclesiastes 10:1 Go To Ecclesiastes 10
The Apostolic Constitutions
AD 375
“Dead flies spoil the whole pot of sweet ointment,” and “when a king hearkens to unrighteous counsel, all the servants under him are wicked.” So one scabbed sheep, if not separated from those that are whole, infects the rest with the same distemper; and a person infected with the plague is to be avoided by all; and a mad dog is dangerous to everyone that it touches. If, therefore, we neglect to separate the transgressor from the church of God, we shall make the “Lord’s house a den of thieves.” .