Who is Jiang Gong in "Prosperity, Jiang Gong is here, all forgive"? What does it matter to build a house?

Jiang Gong refers to Jiang Taigong and Jiang Ziya. Most people can write, but neither can Jiang Taigong.

According to legend, Jiang Ziya's wife is a jinx, and Jiang Taigong unfortunately found her. She also abandoned the squire. After Jiang Taigong got the list of gods, he also went to Jiang Taigong to worship God. Jiang Taigong was angry at the sight of her, and casually scolded a sentence, You are a god of plague. With a whip in her hand, Jiang Taigong's wife became a god of plague. She wandered around, only where Jiang Ziya was, she dared not go, so people, especially those on the farm, liked to post. Jiang Taigong is so unforgivable. Houses are also built to ward off evil spirits.