I remember reading something along the lines of "what can be better than to serve to someone who is better than you" in my philosophy class back in the days. I was pretty sure that I read that in the Trial of Socrates until I wasn't able to find it. Any ideas?
A first approximation...
Plato, Apology, 29b:
But I do know that it is evil and disgraceful to do wrong and to disobey him who is better than I, whether he be god or man.