How can one be self-serving without being self-centered?

One time I asked- "How can one be self-serving without being self-centered or selfish?"

I really wanted to know.

Thirty years passed and I asked again. Recently, I received an answer to my question.

The self is in everything. When you see it, be of service to it in any way you can. Look for the self everywhere, also see it in your desire to find it.

Be at service to this self-in-all-things at all times, and detach from the outcome.