Why did da ji kill Bigan?

Jiang Ziya lived in the music world and made a living by divination. Da ji was offended by burning pipa essence. Da ji wants Zhou Wang to build a deer platform, and Ziya is responsible for supervision. On the deer platform, da ji invited a group of foxes. When you get drunk, you show your true colors. I can see better than serving. Da ji was frightened, so he tried to do harm. Da ji was glad to kill Bigan. He and Zhou Wang were singing and dancing in the Star-Picking Building.