What does it mean to have everything going smoothly and be filled with gold and silver?

Each source of water: There is plenty of water everywhere. Later, it is also used as a metaphor for doing things easily and smoothly. The words come from "Mencius Li Lou Xia".

Smooth sailing: describes doing things very smoothly.

The whole sentence means that if you are tactful and make good use of various social relationships, you will have a smooth journey in the business world. In the end, I made a lot of money, and it was filled with gold and silver.

This method of making money based solely on relationships is a social evil.