Another passage from Marcus that screams amor fati. You 'live with the gods' when you accept and love your fate. This means being 'content with your lot' and doing what the gods wish you to do.
What is unique about our nature as human beings? Our ability to reason and think. This is the divine portion in us that sets us apart from so many other living organisms. We live according to nature when we use what nature gave to us - our ability to think and reason.
(see also Citadel p. 123, 265-266