During the reign of Tang Zhen Guan, before Xue Ren Gui achieved anything, and his wife live in an old cave, but had food and clothing thanks to Wang Mao Sheng's support. Later, Xue Ren Gui joined the army, following Emperor Taizong Li Shimin's Eastern Expedition. Due to Xue Ren's efforts in putting down the the Liao rebellion, he gained great credit and was called "The Duke of Pacifying Liao."
The high-ranking officials and generals came to the palace to send gifts to celebrate his rise to dukedom, but they were politely declined by Xue Ren Gui . He only received Wang Mao Sheng's "two fine wine." When the jars were opened, those in charge of the unsealing were scared, for it was not wine but the water!
"Reporting the Duke, this person dare to mock you, please punish him!" Xue Ren Gui listened but did not get angry, and ordered a bowl to be filled, and in public he drank drink three bowls sent Wang Mao Sheng's clear water. The civil and military officials were puzzled, but after drinking three bowls of water, Xue Ren Gui said: "I used to be in distress, but survived thanks to the Wang household's help, without them I do not have today's wealth. I do not accept fine wine and do not take gifts, I only want my brother Wang's water, a hedge between keeps friendship green. " Since then, Xue Ren Gui and Wang Mao Sheng have a very close relationship and thus the proverb "君子之交淡如水 (a hedge between keeps friendship green)" was passed down.