Commentary on Meditations: B7:55

Do not look around at the directing minds of other people, but keep looking straight ahead to where nature is leading you both universal nature, in what happens to you, and your own nature, in what you must do yourself. Every creature must do what follows from its own constitution. The rest of creation is constituted to serve rational beings (just as in everything else the lower exists for the higher), but rational beings are here to serve each other. So the main principle in man's constitution is the social. The second is resistance to the promptings of the flesh. It is the specific property of rational and intelligent activity to isolate itself and never be influenced by the activity of the senses or impulses: both these are of the animal order, and it is the aim of intelligent activity to be sovereign over them and never yield them the mastery - and rightly so, as it is the very nature of intelligence to put all these things to its own use. The third element in a rational constitution is a judgement unhurried and undeceived. So let your directing mind hold fast to these principles and follow the straight road ahead: then it has what belongs to it.

An excellent passage from Marcus!  In here, he again outlines our duties with regard to the Universe, and to others and to ourselves.

With regard to universal nature, we must accept it.  What happens outside of our control simply must be.  It does no good to take pleasure in it nor to be disturbed by it.  We simply have to accept it and decide what our attitude will be with regard to events out of our control.

What makes humans unique is their constitution and capacity to reason - to think.  Things that do not and cannot think are designed to serve those that can think.  And those things that can think are designed to serve and help each other.  Our duty to others is service.

With regard to ourselves, we must resist the "promptings of the flesh."  Pleasure is not the sole good.  Animals act out of impulse.  Humans do not (or ought not).  I believe it was Socrates who said something along the line of: "you should eat to live, not live to eat."  The same idea can be applied to all impulses.

Lastly, humans ought to develop the proper capacity to judge.  We ought to use reason and logic (god-given gifts).  And when we use our god-given gifts, let us use them "unhurried and undeceived."

(see also Citadel p. 130, 267)