(Clearwisdom.net) During the period of the South-North Dynasty, there was a kingdom called Tuguhun, which was established by the Xianbei ethnicity at the Northwestern border region. Acai was the emperor of this kingdom.

Acai had twenty sons, each one of whom was strong and skilled at fighting. Each had his unique expertise. When Acai was very ill, he called all of his sons together and asked each one of them to give him one arrow. He then said to his younger brother, Mu Liyan, "Please take one arrow here and break it." Mu Liyan easily broke the arrow. Acai then said, "Please take nineteen arrows here and break them." Mu Liyan could no longer break the bundle of arrows. Acai said, "Now do you understand? One arrow is very easily broken, while a bundle of arrows is hard to break. As long as all of you work together with one heart, our kingdom will be stable."

What Acai said, "One arrow is easily broken, while a bundle of arrows is hard to break," as well as what has been said by the ancient people, "When people's hearts are joined together as one, even Mount Tai can be moved," pointed out the importance of people working together with one heart.