It means that the width of the sea can accommodate many rivers; Metaphor a person's broad-minded, can contain everything. This sentence means to be broad-minded and broad-minded, which is also the embodiment of one's self-cultivation.
People regard people with a sea of hearts as respectable people. At the same time, it also has an all-encompassing meaning, which is often used to describe magnificent and indescribable things, so it is described as "all rivers run into the sea"
source
"Thanks to modesty, tolerance is great" was first seen in the self-encouragement couplets written by Yuan Keli, Prince of the Ministry of War in the Ming Dynasty, in his own Fu in Suizhou, Henan. Two hundred years later, Lin Zexu, a national hero in the late Qing Dynasty, wrote an eight-character couplet in his study: "A hundred rivers are full of tolerance; The wall stands thousands of miles, and there is no desire. " It is meant to be a metaphor for a broad mind like the sea. This is to describe people's extraordinary bearing with the infinite capacity that the sea can accommodate countless rivers and streams.