Stop pedestrians from thirsty and turn off riot fighters. What's the story of this couplet?

There are couplets on both sides of the city gate, which read: I am willing to stop pedestrians' thirst and turn off riot. According to legend, this couplet was inscribed by a businessman named Li Hua in southern Fujian during Guangxu period of Qing Dynasty. How does a businessman write couplets for Mei Guan? Here's another story! Li Hua was born in a wealthy businessman family. The father went through hardships and earned an industry, expecting his son to study hard. However, although Li Hua is clever, he is naughty and active by nature and refuses to study. One day, Li Hua's father received a letter from a close friend, saying that he was doing business in Shaozhou, Guangdong, and invited him to do business together. But Li Fu didn't want to go, so he asked his son to go instead of his father and learn to do business with him, so that he could develop well in the future. Li Hua was bored at home and agreed happily. A few days later, Li Hua set out with his servants and goods. After arriving in Nan 'an, due to the tiredness of the journey, I didn't inquire about Meiling in detail, so I had an early rest in the park. Early the next morning, when Li Hua and his servants arrived at Meiling Station, the courier warned them that some hungry people went up the mountain to be bandits and often robbed property. Li Hua didn't think so, but when they reached a ravine in Meiling, a group of robbers rushed down from the mountain, pushed them to the side of the road, picked up the goods and left, and soon disappeared. Li Hua was very remorseful and went to Shaozhou empty-handed. After arriving at the destination, Li Hua's father's friend arranged for him to work in the store and personally taught Li Hua how to know and adjust the goods. Because Li Hua is a thinker, he bought a batch of goods to take home. As there were many goods, Li Hua invited a guard to escort him through Meiguan. Because of this, I finally arrived at Nan 'an House safely through Meiling. When Li Hua was in Nan 'an, he remembered the scene when he passed Meiling in the inn. After some consideration, he began to write down the couplet "Stop the thirst of pedestrians and never make trouble for passengers", and then entrusted the store to the local government. The implication is that he hopes the government will strengthen the anti-theft safety of Meiling Post Road. Later, in order to warn merchants from the south to the north, someone wrote a couplet written by Li Hua on the Meiguan Pass to warn future generations.