During the Spring and Autumn period, there was a small vassal state called Sui (in present-day northern Hubei). One day, the Marquis of Sui was out sightseeing and climbed a small hill by the Fugong River. As he walked forward, he suddenly spotted a massive snake over ten feet long lying on the roadside, startling him. Looking closer, he saw the snake's vital spot was nearly severed. The snake gazed at the marquis with a pleading look, as if saying, "Save me! I will surely repay you!"
The Marquis of Sui was astonished. A devout believer in the divine, he declared, "This great serpent must be a spirit in disguise!" He ordered his men to bring medicine, personally applied it to the snake's wound, and carefully bandaged it.
The snake nodded gratefully at the Marquis of Sui several times before slowly slithering away.
A year later, the Marquis of Sui returned to the same hill for a leisurely outing. As he admired the picturesque landscape, he suddenly spotted a massive snake gliding slowly toward him across the river. When it crawled ashore, he examined it closely and noticed a faint, healed scar around its neck—the very snake he had rescued the previous year. The snake held in its mouth a pure white luminous pearl, about an inch in diameter, radiating an extraordinary glow—a truly rare treasure.
The snake spat the luminous pearl into Sui Hou's palm, bowed its head three times, and slithered away. Overjoyed, Sui Hou brought the pearl home. That night, he placed it in his room, and the once pitch-black chamber instantly glowed as brightly as if bathed in moonlight.
Later, people called this luminous pearl the "Marquis of Sui's Pearl" and the small hill "Snake-Severing Mound." Today, the idiom "Marquis of Sui's Pearl" is used to refer to precious pearls or treasures, and also to praise a person's virtue.
Source: *Huainanzi*, Chapter "Surveying Obscurities"
Meaning of the Idiom: Later, the Chinese idiom "隋侯之珠" came to describe refer to precious pearls or treasures, and also to praise a person's virtue.