The Talmud in Kiddushin 31a tells the story of Dama ben Netina, a gentile merchant of Ashkelon who became, in the rabbinic imagination, the standard for filial honor. The exempla collection edited by Moses Gaster in 1924 preserves the tale as number 188.
The priests of the Temple in Jerusalem came to Dama's warehouse one day in search of a particular precious stone to complete the choshen, the breastplate of the High Priest that bore the names of the twelve tribes (Exodus 28:17-21). The stone was in a locked chest, and the key was in his father's pocket, and his father was asleep on top of the chest.
Dama would not wake him. He stood before the priests and shook his head. Come back later, he told them. My father is resting, and I will not disturb him. The priests, assuming he was simply negotiating for more money, raised their offer. Then raised it again. The sums climbed into the many thousands of dinars. Dama still refused. The honor of his father was not for sale at any price.
Eventually his father woke on his own. Dama opened the chest, took out the stone, and sold it for the original, modest price the priests had first offered. He would not profit from the moments his father had slept.
The story does not end there. Heaven rewards acts like this with exacting precision. The next year Dama's herd produced a parah adumah, a flawless red heifer, the rarest and most valuable animal in the Jewish sacrificial economy, used for the purification ritual of Numbers 19. Jewish priests came to buy it. Dama named a price equal to the sum he had given up by refusing to wake his father, and they paid. The mitzvah of kibbud av, honoring one's father, was repaid with interest, in the exact currency he had declined. Heaven is a meticulous accountant of unnoticed kindnesses.