This was because the Six-Eared Macaque was more confident that he could obtain the Ruyi Jingu Bang (Needle Form) in the Dragon Palace.
The Six-Eared Macaque was also interested in other Dharma treasures. However, what he needed the most now was naturally a suitable weapon.
Moreover, Su Qianqian had told him about the Ruyi Jingu Bang (Needle Form) of the Dragon Palace.
From the Six-Eared Macaque's point of view, Su Qianqian had learned about it from Journey to the West.
Therefore, the Six-Eared Macaque would follow the instructions in the "Heavenly Book" and obtain the Ruyi Jingu Bang (Needle Form). He would kill the Monkey King and become the Great Sage Equal to Heaven!
The Six-Eared Macaque followed Su Qianqian all the way to the west without hesitation.
