Because my mom is the oldest sister, she always had to set the example for her 2 younger sisters. So whenever she would disobey her parents, my grandma told her this proverb to explain why she needed to be a good role model. This saying actually annoyed my mom a lot, because although she understood the message of it, she felt like everything she was doing as an adolescent was being analyzed, to make sure her younger sisters would be happy and good.
윗물이 맑아야 아랫물이 맑다
Weet mool ee mal ga ya ah rae mool ee malg dah.
High water clear so bottom water clear.
The water at the top of the mountain has to be clear for the water at the base of the mountain to also be clear.
I think this type of “role model” sentiment is valid, but instills Asian family household stereotypes and expectations. There is almost a lack of freedom for the eldest child, because he/she is reprimanded for making mistakes, exploring less developed paths, or even just not listening to his/her parents. For example, I was not allowed to quit piano lessons or go to a PG-13 movies, because it could negatively affect my younger sister.
Although this proverb was always used in the context of sibling relationships in my family, it could also apply in a wider scope. Because the basis of the proverb pertains to being a role model, it could be used in other hierarchical systems, such as a place of work, an organization, or a class setting. If the person at the top (CEO / President / Teacher) is kind and understanding, the people that work alongside or beneath that person will also be respectful of others. While in the case that the “water at the top of the mountain” is rude and disrespectful, people will feed off of that negative energy and perpetuate these bad actions.