Jiseong imyeon gamcheon ida means “sincerity moves heaven.” That means that if you exert yourself to the utmost, you will get a good result despite very difficult work.
The origin of this proverb is a folk tale about Jiseong (who can’t walk) and Gamcheon (who can’t see), and the good luck they get from their friendship. They were beggars who helped each other. Gamcheon carried Jiseong on his back, and Jiseong gave Gamcheon directions. One day, they discovered a big gold nugget after drinking water from a mountain spring. They asked a passing peddler to divide the gold. However, the peddler was frightened away because he thought the gold was a big snake.
After that, they asked a hunter to part the gold. The hunter divided it in two because he saw the gold as a stone. Now, the two men each had half of the gold. A few days later, they went to a temple where a Buddhist monk suggested they give the gold as an offering and pray for their parents for 100 days. Amazingly, after 100 days of prayer, Gamcheon opened his eyes and could see, and Jiseong stood up and could walk.
This is where the proverb that means sincerity moves heaven comes from.