In the first Legend of Zelda game, this was a phrase used by the Moblins when they gave you money. Aka "rupees".
The Moblins could be found underneath statues, trees or inside of caves, where they hid the entire game until Link stumbled upon them. Then they would give him their money and disappear.
What, exactly, the Moblins, who were usually Link's enemies, were doing giving him money, I do not know. Perhaps they were rebels against the tyannical rule of Ganon, which would certainly explain both why they were giving money to Link, and the need to keep it a secret to everyone.