The Stoic slogan was to live in agreement with nature, and it means more than it sounds like. Their universe is a single ordered whole, held together and directed by reason - the logos - of which each human mind is a fragment. Living in agreement with nature is living according to the reason you were built with, in a world that is running on the same principle.
These passages cover the divine, providence, fate, and the constant flux of a cosmos in which nothing individual lasts and nothing is genuinely lost.
50 passages
"See what great things they do every day, how much they divide amongst us, with how great crops they fill the earth, how they move the seas with convenient winds to carry us to all shores, how by the fall of sudden showers they soften the ground, renew the dried-up springs of fountains, and call them into new life by unseen supplies of water."
"To Nature, who bestows all things and takes them away, the man who has learnt his lesson and respects himself says: 'Give what is thy good pleasure, take back what is thy good pleasure'; and this he says not boasting himself but only listening to her voice and being of one mind with her."
"Foolish people who know not the truth hold them answerable for storms at sea, excessive rain, and long winters, whereas all the while these phenomena by which we suffer or profit take place without any reference whatever to us: it is not for our sake that the universe causes summer and winter to succeed one another; these have a law of their own, according to which their divine functions are performed."
"Either all comes to pass from one fountain of mind, as in a single organic body, and the part must not find fault with what is for the good of the whole; or else there are atoms, nothing but a mechanical mixture and dispersal."
"Now, if indeed it is so, be certain of this that, if it ought to have been otherwise, the gods would have made it so; for were it just, it would also be possible, and were it accordant with Nature, Nature would have brought it about."
"Finally, having traversed every one of the realms below, it soars to the highest heaven, enjoys the noblest of all spectacles, that of things divine, and, remembering itself to be eternal, reviews all that has been and all that will be for ever and ever."
"And by 'Universal Nature employing these indifferently', I mean that in the natural order they happen indifferently to what comes to pass and follows upon an original impulse of Providence, whereby from an original cause it had an impulse to this world order, having conceived certain principles of what should come to be, and appointed powers generative of substances and changes and successions of the like kind."
"The work of the gods is full of Providence: the work of Fortune is not divorced from Nature or the spinning and winding of the threads ordained by Providence."
"Watch and see the courses of the stars as if you ran with them, and continually dwell in mind upon the changes of the elements into one another; for these imaginations wash away the foulness of life on the ground."
"Thus, every part of me will be assigned its place by change into some part of the Universe, and that again into another part of the Universe, and so on to infinity."
"Let your imagination dwell continually upon the whole of Time and the whole of Substance, and realize that their several parts are, by comparison with Substance, a fig-seed; by comparison with Time, the turn of a gimlet."
"All things are woven together and the common bond is sacred, and scarcely one thing is foreign to another, for they have been arranged together in their places and together make the same ordered Universe."
"To those who ask the question: 'Where have you seen the gods, or whence have you apprehended that they exist, that you thus worship them?' First, they are visible even to the eyes; secondly, I have not seen my own soul and yet I honour it; and so, too, with the gods, from my experiences every instant of their power, from these I apprehend that they exist and I do them reverence."
"You have somehow made yourself an outcast from the unity which is according to Nature; for you came into the world as a part and now you have cut yourself off."
"Still, they do have a place to throw rubbish into, whereas Universal Nature has nothing outside herself, and yet the astonishing thing in her way of working is that, having fixed her own limits, she is ever changing into herself everything within those limits that looks as though it were going bad and getting old and useless, and out of these very things creating again others that are young, in order that she may need no substance from outside nor require any place to throw away what begins to decay."
"We can serve the greater commonwealth even when we are at leisure; indeed I am not sure that we cannot serve it better when we are at leisure to inquire into what virtue is, and whether it be one or many: whether it be nature or art that makes men good: whether that which contains the earth and sea and all that in them is be one, or whether God has placed therein many bodies of the same species: whether that out of which all things are made be continuous and solid, or containing interstices and alternate empty and full spaces: whether God idly looks on at His handiwork, or directs its course: whether He is without and around the world, or whether He pervades its entire surface: whether the world be immortal, or doomed to decay and belonging to the class of things which are born only for a time?"
"Asia and Europe are corners in the Universe; every sea, a drop in the Universe; Mount Athos, a clod of earth in the Universe; every instant of time, a pin-prick of eternity."
"Reflect upon the multitude of bodily and mental events taking place in the same brief time, simultaneously in every one of us; and so you will not be surprised that many more events, or rather all things that come to pass, exist simultaneously in the one and entire unity, which we call the Universe."
"It is said, "God does not bestow benefits." Whence, then, comes all that you possess, that you give or refuse to give, that you hoard or steal? whence come these innumerable delights of our eyes, our ears, and our minds? whence the plenty which provides us even with luxury--for it is not our bare necessities alone against which provision is made; we are loved so much as actually to be pampered-- whence so many trees bearing various fruits, so many wholesome herbs, so many different sorts of food distributed throughout the year, so that even the slothful may find sustenance in the chance produce of the earth?"
"One vital spirit is distributed in irrational creatures: one mind spirit is divided in rational creatures; just as one element earth is in all earthy things and we see by one light and breathe one atmosphere, all that have sight and vital spirit."
"Everything that your eyes look upon will be changed almost in a moment by Nature which orders the Whole, and out of the material it will create other things, and again out of their material others, in order that the world may be ever fresh and young."
"But if they took no counsel about me as an individual, surely they did for the common good, and as the present follows upon that by way of consequence, I am bound to welcome and to love it."
"One helps in one way, one in another, and ex abundanti even he who finds fault and tries to resist or destroy what is coming to pass; for the Universe has need even for such a one."
""According to this," argues our opponent, "you are under no obligation to the sun or the moon; for they do not move for your sake alone." No, but since they move with the object of preserving the balance of the universe, they move for my sake also, seeing that I am a fraction of the universe."
""Nature," says my opponent, "gives me all this." Do you not perceive when you say this that you merely speak of God under another name? for what is nature but God and divine reason, which pervades the universe and all its parts?"
"If he is a foreigner in the Universe who does not recognize the essence of the Universe, no less is he a foreigner, who does not recognize what comes to pass in it."
"Nothing in thy good time is too early or too late for me; everything is fruit for me which thy seasons, Nature, bear; from thee, in thee, to thee are all things."
"That which knows the beginning and end and the reason which informs the whole substance and through all eternity governs the Whole according to appointed cycles."
"Whenever you feel something hard to bear, you have forgotten ( a ) that all comes to pass according to the Nature of the Whole, ( b ) that the wrong is not your own but another's, further ( c ) that all that is coming to pass always did, always will, and does now everywhere thus come to pass, ( d ) the great kinship of man with all mankind, for the bond of kind is not blood nor the seed of life, but mind."
This is the part of Stoicism modern readers most often skip, and skipping it costs something: the ethics is standing on it. The reason to accept what happens is that it comes from an order that is going somewhere; the reason to treat every person as kin is that the same reason runs through all of them.
Marcus writes nearly all of this, and he is also the one who hedges. Providence or atoms, he keeps saying - if the universe is a rational whole, act accordingly; if it is only a churn of particles, you still have your own mind to govern. The ethics is meant to survive either answer.