One of the themes of Meditations is our need to accept the things that are outside our control.
To play the hand we’ve been dealt:
“The spot where a person decides to station himself, or wherever his commanding officer stations him— well, I think that’s where he ought to take his stand and face the enemy, and not worry about being killed, or about anything but doing his duty.” (7.45)
To treat misfortune as an opportunity for growth:
"Just as you overhear people saying that “the doctor prescribed such-and-such for him” (like riding, or cold baths, or walking barefoot …), say this: “Nature prescribed illness for him.” Or blindness. Or the loss of a limb. Or whatever. There “prescribed” means something like “ordered, so as to further his recovery.” And so too here. What happens to each of us is ordered. It furthers our destiny." (4.8)
To not worry about what might not happen:
“Don’t let your imagination be crushed by life as a whole. Don’t try to picture everything bad that could possibly happen. Stick with the situation at hand, and ask, “Why is this so unbearable? Why can’t I endure it?” You’ll be embarrassed to answer.” (8.36)
To not be surprised when people act according to their nature:
“To expect a bad person not to harm others is like expecting fig trees not to secrete juice, babies not to cry, horses not to neigh— the inevitable not to happen. What else could they do— with that sort of character? If you’re still angry, then get to work on that.” (12.16)
To let go:
“Not “some way to sleep with her”— but a way to stop wanting to.
Not “some way to get rid of him”— but a way to stop trying.
Not “some way to save my child”— but a way to lose your fear.” (9.40)