The Richest Man in Babylon by George S. Clason (pg. 65)

“Therefore, be not swayed by the fantastic plans of impractical men who think they see ways to force thy gold to make earnings unusually large. Such plans are the creations of dreamers unskilled in the safe and dependable laws of trade. Be conservative in what thou expect it to earn that thou mayest keep and enjoy thy treasure. To hire it out with a promise of usurious returns is to invite loss.