Matthew Henry Commentary Ecclesiastes 10:1-3

"Dead flies cause the oil of the perfumer to send forth an evil odor; [so] doth a little folly outweigh wisdom and honor. A wise man`s heart is at his right hand; but a fool`s heart at his left. Yea also, when the fool walketh by the way, his understanding faileth him, and he saith to every one [that] he is a fool." — Ecclesiastes 10:1-3 (ASV)

Those who profess their faith, in particular, should avoid all appearances of evil. A wise person has a great advantage over a fool, who is always at a loss when they have anything to do. Sin is the reproach of sinners, wherever they go, and shows their folly.