Why do you have to write the clause "When Jiang Taigong is here, the gods will abdicate" when building a new house?

It is said that in the early Western Zhou Dynasty, there was a Songjiazhuang to the east of Jiangyuan, the hometown of Jiang Taigong. The owner of the village, Song Yi, has a wealthy family. He and Jiang Taigong were good friends who burned incense and swore an oath. One year, Song Yiren thought his house was dilapidated and wanted to build a new one. So, he found someone to select a piece of Feng Shui land and started construction on a good and auspicious day. However, it was not covered even after several attempts. The first time the walls were built around the house. A strong wind blew it down. Just after the fourth beam was put up for the second time, all four beams of the five rooms were broken in an instant. When it was rebuilt for the third time, all the firewood and grass were laid on the roof, and there was a big fire. Burned clean. Reluctantly, Song Yiren had no choice but to leave the main room behind and hastily built a couple of side rooms to live in. Soon, Jiang Taigong returned to his hometown from Qi to visit relatives. On this day, he had nothing to do and went to visit his good friend Song Yiren. After not seeing each other for many years, they were extremely close. The two never talked about the ups and downs after separation. At this time, Jiang Taigong saw that the back hall of Song Yiren was still in ruins and the main room was not built. Jiang Taigong couldn't figure it out, so he asked Song Yiren what was going on. Song Yiren, with a sad face, told Jiang Taigong in detail about the misfortunes he encountered when building a house. When Jiang Taigong heard this, he understood immediately. He smiled slightly and said, "It turns out it's such a trivial matter. Don't worry, my dear friend, the day after tomorrow is the auspicious day of the zodiac, and the purple star is coming, so you can just start building a house." Two days passed in a flash. When the time came for the beam to be raised, Jiang Taigong came to the new house, stood next to the purlin, and muttered something: "Ghosts and gods from all over the world, wash your ears and listen. Grandpa is here, and everyone should go to his place." The next day, Song Yiren started work with hesitation, and it turned out to be true. With a few words from the grandfather, Song Yiren built the house without incident. In just a few days, the new house was built smoothly. What's going on? It turns out that when Song Yiren started to build a new house, ghosts and gods from all over the world came to fight for the territory and the incense. Song Yiren was frightened by the trouble caused by this. This time when the house was being built, ghosts and gods from all over came again after hearing the news. Just when they were about to make a fuss, Jiang Taigong suddenly appeared in front of them, and they were all trembling with fear. Because they are all conferred by Jiang Taigong, and more importantly, Jiang Taigong has a magic whip, so he is afraid that the guilty will be tortured in his hands. Therefore, when Jiang Taigong said that and stood inside the house, they all ran away in fear.

Later, this incident spread, and all the people who built a new house had to follow the example of Song Yiren. In order to seek good luck when they went up the beam, they wrote a picture: "The beam is in the zodiac, and the pillars are cleverly erected." The couplet of "Every Purple Star". On the flower purlin, the clause "Jiang Taigong, the gods abdicate here" is written. Some people also tie a pair of chopsticks and a bunch of copper coins with a red-headed rope on the flower purlin, which means: food, shelter and money to spend. I want Jiang Taigong to live here for a long time and keep his family safe forever. This custom has been followed for more than three thousand years, and most people still use this custom when building houses today.