During the Spring and Autumn period, Ji Kangzi, a high-ranking official of the Lu state, resided in Fei City (present-day Fei County, Shandong). Though his official title was that of a minister, his power far exceeded even that of the reigning Duke Ai of Lu.
Ji Kangzi, seeking to expand and consolidate his power, planned to attack and annex a small neighboring state called Zhuanyu.
Confucius's disciples Ran You and Zi Lu were both advisors to Ji Kangzi at the time. Finding it difficult to remonstrate with him, they sought Confucius's guidance. Confucius suspected it was Ran You's idea. Ran You replied, "This was Ji Kangzi's plan; both Zi Lu and I wanted to stop him."
Confucius said, "Since you both assist Ji Kang, you should do your utmost to dissuade him." Ran You added, "However, Zhuanyu's power is growing stronger by the day. If we do not seize it now, it may become a threat later."
Confucius replied, "That is not right! Ruling a state does not require worrying about land or population size—one should instead focus on how to bring peace and prosperity to the people. Once the people are settled, the state will grow strong and wealthy. Only then can you promote benevolent governance and ritual music to attract distant peoples, allowing them to live in peace. Yet you two assist Ji Kang, causing distant peoples to turn away and refuse to submit, the people to grow disloyal and discontent, and the state to be divided and unable to unite. With your own state on the verge of collapse, you still plan to attack Zhuanyu by force. I fear Ji Kang's troubles lie not with Zhuanyu, but within his own palace walls."
"The 'Xiao Wall' was the screen wall before the ruler's palace gate. Confucius meant that Ji Kang's troubles lay within, not without. This story also gave rise to another idiom, 'Trouble arises within the Xiao Wall,' describing internal strife."
Later, the idiom "falling apart" came to describe a nation or group that is fragmented, shattered, and beyond repair.
Source: *The Analects*, Chapter "Ji Shi"
Meaning of the Idiom: Later, the Chinese idiom "分崩离析" came to describe a nation or group that is fragmented, shattered, and beyond repair.