Proverbs 11:1 (ESV)

1 A false balance is an abomination to the LORD, but a just weight is his delight.

Men can and do take unfair advantage of others in their business dealings. With their dishonest and deceiving practices, they may enjoy earning more profit than they deserve. But the Lord, who sees through it all, is not pleased. He hates such corrupt trade.

The man who is fair in all his dealings will not fail to profit in the long run. In the meantime, he enjoys the priceless profit of knowing that his honest dealings please his Lord.