Why do you always post the words "Qinglong, White Tiger" at the wedding door?

Now, when couples get married here, they all post a white tiger in Yi Long at the gate. It is said that this has a history. According to legend, during the Qianlong period of the Qing Dynasty, a middle-class family in the south of the Yangtze River set a wedding date for their son. But for some reason, his father went to the fortune teller to calculate whether the date was ok. The fortune teller asked the date of birth of both men and women and calculated it. He was frightened and said, "The date you set is the worst day for getting married." Hearing this, my father was very upset. Just as I was about to leave, the fortune teller suddenly turned from surprise to joy and said, "Go slowly. It is the best day to get married in other people's homes, but it is the best day for your children to get married. Don't worry, go back and do it, someone will help you. " Father went back happily. The wedding was held as scheduled, but when I was visiting the church, it rained heavily and thunderstorms. Coincidentally, Ganlong went down to the south of the Yangtze River and made a private visit with Liu Yong traveling incognito, and happened to come to the wedding gate, so they had to go downstairs to take shelter from the rain. Seeing this, the host invited Gan Long and Liu Yong to hold a wedding reception at home. At the wedding banquet, the owner of this family told Gan Long about the marriage and expressed his gratitude! It has been more than a year since Gan Long and Liu Yong returned to the palace. One day, Gan Long suddenly had a whim: This is not good. If people get married, my son will stand in front of the door. That's not bad. Don't have a son. Why don't you compete with me? So he sent Liu Yong to visit and gave birth to a daughter. If he gave birth to a son, he asked Liu Yong to find a way to break the fate of the child. So Liu Yong disguised himself and came to this family again. It happened that everyone else in the family was out of the door, only the child's grandmother was playing with a white and fat boy. Liu Yong had a brainwave and pretended to beg for tea and came to this house. Chatting with grandma while drinking tea. He pretended to praise and said, "Look, your grandson's heaven is full, and his place is Fiona Fang. When he grows up, he will be an official of seven or eight products. " Grandma can't read and doesn't know the rank. Hearing Liu Yong's praise, he said modestly, "Seven products and eight products are not bad. I hope that I can be an official with two products. " . Lu Yong also helpless, had to go back. After many years, sure enough, the children of this family got the first prize. The story was passed on from mouth to mouth and spread slowly in the local area. When children get married, the people put green dragons and white tigers on both sides of the gate instead of Ganlong and Liuyong. Pray for peace and evil spirits. It has gradually become a custom!