This sentence talks about the value of favors. If you are a rich and powerful person, even if no one of your relatives lives in the mountains, there will be people who come to visit you in person. If You are a poor person. Even if you live on the streets of a bustling city with people coming and going, no one will pay attention to you, let alone recognize you there. The second half of the sentence is - be careful when you first meet people, and never have any resentment in your heart until you grow old.

It means that every time you deal with people and the world, you should always maintain the mentality and appearance of meeting others for the first time. If you do this, even when you are old, you will not have any differences with others because of the differences in the way of dealing with the world. Forging a bridge creates resentment. From "Zengguang Xianwen".