The Stoics of ancient times had something profound to say about everything, it seems. The reason for that, of course, is because what they actually describe is a way of thinking, a way of life. As you can gather from the article, there is also some religious context which is really fairly optional. Or at least you could substitute your own religious beliefs in with all the talk about God. But you can apply Stoic principles to really any situation you could think of. No kidding, and as implausible as it sounds, I've thought of things I read from Marcus Aurelius in the heat of combat, just having sort of popped into my mind. Though I will say that I'd been through a really tough stretch of life around that time, and had been reading some of the Stoics (among others) as an escape. So it's just as likely chance as anything else that brought that dude's writing to mind. Marcus Aurelius is kind of held up among the other greats of Stoic philosophy, but Seneca is really IMO the best. Epictetus is a close second. But Marcus Aurelius is popular because of course he was the Emperor, and never intended on publishing his diaries (which we today call "Meditations"). You want a rabbit hole that will save your life, perhaps not only figuratively? Here it is!