Solomon
Proverbs 20:17ESV·traditional attribution

Bread gained by deceit is sweet to a man, but afterward his mouth will be full of gravel.

Matthew Henry Presbyterian

Note, 1. Sin may possibly be pleasant in the commission: Bread of deceit, wealth gotten by fraud, by lying and oppression, may be sweet to a man, and the more sweet for its being ill-gotten, such pleasure does the carnal mind take in the success of its wicked projects. All the pleasures and profits of sin are bread of deceit.

John Gill Reformed Baptist

Bread of deceit is sweet to a man,.... Which may be understood of sin in general, which is bread to the sinner, he eats it: it is called "the bread of wickedness", Pro 4:17; but it is but poor bread, no other than ashes Isa 44:20; it is "bread of deceit"; there is a deceitfulness in all sin; it is in appearance fair and pleasant...

Jamieson-Fausset-Brown Reformed

Bread . . . sweet--either as unlawfully (Pro 9:17) or easily obtained. mouth . . . gravel--well expresses the pain and grief given at last.