sweat of one's brow

A reference to Genesis 3:17 and 19 in the Bible (King James Version; spelling modernized): “And unto Adam he [God] said, because thou hast hearkened unto the voice of thy wife, and hast eaten of the tree, … In the sweat of thy face shalt thou eat bread, till thou return unto the ground: …”, meaning that due to disobedience to God, humans would henceforth have to exert labour for their food, causing their brows or foreheads to perspire.

• "So anyhow Terry brought the three pints Joe was standing and begob the sight nearly left my eyes when I saw him land out a quid. O, as true as I'm telling you. A goodlooking sovereign. / ― And there's more where that came from, says he. / ― Were you robbing the poorbox, Joe? say I? / ― Sweat of my brow, says Joe. 'Twas the prudent member gave me the wheeze."
• "Making matters worse, these courts developed a new theory to justify the protection of factual compilations. Known alternatively as "sweat of the brow" or "industrious collection," the underlying notion was that copyright was a reward for the hard work that went into compiling facts."

• sweat of one's brows
• sweat of one's face

• sweat of the brow