This sentence comes from a couplet written by Zeng Guofan. The first part comes from Su Shi's "Traveling with Cai Jiu in Haizhou Shishi Lianxian" (Shiye), and the second part comes from Wang Anshi's "Boya".
Extended data:
Poetry background:
Ceng Gong led the Xiang army to attack Nanjing Houwei Town, which made great contributions to Gaozhen. At this time, if he transfers his troops to revolt, it may become the best time for self-reliance. General Xiang collectively hinted: half of the southeast has no owner, and your master does not care! The weight of the tripod seems to be asking! Hope Ceng Gong raised his arm and shouted.
At this time, he thought about it and wrote down the famous couplet: leaning on the sky shines countless flowers in the sea, and running water knows itself. This completely dispelled people's expectation that he was the king and emperor.
References:
Countless flowers in the sea depend on the sky, and a rising tide lifts all boats.