Remember always what the nature of the Universe is, what your own nature is, and how these are related. Remember what part your qualities are of the qualities of the whole, and that no one can prevent you from speaking and acting always in accordance with your nature.
The first part here is a bit confusing and relates, I think to Stoic cosmology that doesn’t really interest me, but the second, is one of Marcus’s central ideas, strongly put. You cannot be forced to act against your nature. You can be coerced, bribed, or cajoled, but always in every moment, you are in the driver seat.
We often don’t want to admit this to ourselves, because the power it gives us is terrifying. “I had to do X because my boss wanted me to”. No, you didn’t. You choose to do it. “No I had to because I need the job.” No, you want the job. Better put – I choose to do what my boss asked because I am not prepared to face the consequences of losing my job. That’s the real answer, and it might be the right one. But we need to own that, and it isn’t easy.