by the sweat of one's brow

Idioms and Phrases

By hard work, as in The only way he'll succeed is by the sweat of his brow . This figurative usage appears in the Bible (Genesis 31:9), where Adam's punishment for eating fruit in Eden is “In the sweat of thy face shalt thou eat bread”—that is, he will have to work for his bread, or living. [c. 1600]