Marcus offers very sound advice when we feel our anxiety starting to rise. At the time of this writing, this passage was particularly useful. I arrived at work on Monday, expecting a quiet week; a week where I'd be able to work on my back log. Instead, there were numerous issues and popped up and multiple fires to fight. I felt the stress and anxiety creep in. Then I came across this passage and recognized I was 'fretting.' I remembered that whatever happens, including all these issues, was brought about in accordance with the nature of the Whole. There was no benefit in getting all riled up and stressed out. All that happened this week, indeed, has happened before and will happen again. This point was driven home to me, because nine years ago, I was in a very similar situation. Back then, I did not have the Stoic framework. But this week I did and I was much more accepting of the situation than I was nine years ago.
If I go back twenty years ago, I recall being stressed out and homesick while I was living in a foreign country. At that time, a good person and dear friend gave me some excellent advice. I was focused on myself and my problem. But he advised me that all through the country and around the world, there were other people in a similar situation as I was in. And that if I remembered that every morning, I would not feel so lonely and feel a kinship with everyone else living through similar circumstances.
All of us humans are in this together. We all come from god's mind, therefore every human's mind is a slice of the divine.
Lastly, we have control over our opinion and attitude. And we get to choose what our attitude will be. Therefore, be present and live in this very moment - be positive.
(see also Citadel p. 38-43, 113, 127, 132)