by the sweat of (one's) brow

Through or because of one's own efforts or hard work. By the sweat of his brow, my father turned a barren little plot of land into the flourishing farm you see today. This pair of entrepreneurs has created a billion-dollar company by the sweat of their brow.

Fig. by one's efforts; by one's hard work. Tom raised these vegetables by the sweat of his brow. Sally polished the car by the sweat of her brow.

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]

If you earn the money that you live on by the sweat of your brow, you earn it through doing hard physical work. Most people are no longer earning their bread by the sweat of their brow.

By hard work. The expression appears to be based on God’s punishment of Adam for eating the forbidden fruit in the Garden of Eden. Not only was Adam expelled, but thereafter he would have to work for a living. The Book of Genesis (3:9) has it, “In the sweat of thy face shalt thou eat bread.” John Donne later (1624) spelled it out: “It was part of Adam’s punishment, In the sweat of thy browes thou shalt eat thy bread.”