English translation …
When you drink water, think of its source (idiom); gratitude for blessings and their well-spring. Don’t forget where your happiness come from. Be grateful for all your blessings!
It basically means when you drink the water remember to think of it’s source or where it came from? Don’t forget it’s origin. The water you are enjoying to sustain your body must not be forgotten or ignored.
On a deeper meaning, it could also mean never forget your origin or roots – where you come from? If someone were to tell you to 饮水思源[yǐn shuǐ sī yuán], he is reminding you of your roots.
If we do not care or remember our roots or origin – are we any different from those bovine animals? Our make up as a people or society need to have a sense of history so that it can act as an archived ballast for our future reference.
If a political party comes to power and won the mandate to govern and rule, it must 饮水思源[yǐn shuǐ sī yuán]. To ignore this is to do it at its own peril. It’s been proven throughout history in the rise and fall of dynasty and kingdom. There is no exception. It applies to all whether as an individual or an organization. It must be so having been decided since time immemorial for us mortals living between heaven and earth!