It was just an image with an interesting quotation on it, an internet meme like any other but the author was purportedly Cicero. Being interested in ancient history, I knew there would likely be a better story around the quotation than the sugary sweet sentiment of the sentence taken out of context.

The quote, as I suspected, wasn't entirely accurate but it was indeed from Cicero's De Natura Deorum, perhaps one of the greatest philosophical tomes which has survived from that time. And time is important here - this book was written 45 years before the birth of Christ and yet the arguments presented in it seem quite modern. Indeed, even atoms are mentioned - the idea that all matter is composed of tiny atoms, while not identical to modern atomic theory, is certainly not new.

In the book, Cicero uses the device of various philosophers arguing to lay out the Stoic, Epicurian, and Academic points of view. The quote in question is found in an Epicurian argument. For more about the main two philosophies read these few pages in another introduction to De Natura.

Cicero, Marcus Tullius
De Natura Deorum, I xix - xx.

English translation by Rackham, H. (Harris), 1933

You Stoics are also fond of asking us, Balbus, what is the mode of life of the gods and how they pass their days. The answer is, their life is the happiest conceivable, and the one most bountifully furnished with all good things. God is entirely inactive and free from all ties of occupation; he toils not neither does he labour, but he takes delight in his own wisdom and virtue and knows with absolute certainty that he will always enjoy pleasures at once consummate and everlasting.

This is the god whom we should call happy in the proper sense of the term; your Stoic god seems to us to be grievously overworked. If the world itself is god, what can be less restful than to revolve at incredible speed round the axis of the heavens without a single moment of respite? but repose is an essential condition of happiness. If on the other hand some god resides within the world as its governor and pilot, maintaining the courses of the stars, the changes of the seasons and all the ordered process of creation, and keeping a watch on land and sea to guard the interests and lives of men, why, what a bondage of irksome and laborious business is his!

We for our part deem happiness to consist in tranquility of mind and entire exemption from all duties.

For he who taught us all the rest has also taught us that the world was made by nature, without needing an artificer to construct it, and that the act of creation, which according to you cannot be performed without divine skill, is so easy, that nature will create, is creating and has created worlds without number. You on the contrary cannot see how nature can achieve all this without the aid of some intelligence, and so, like the tragic poets, being unable to bring the plot of your drama to a demouement, you have recourse to a god; whose intervention you assuredly would not require if you would but contemplate the measureless and boundless extent of space that stretches in every direction, into which when the mind projects and propels itself, it journeys onward far and wide without ever sighting any margin or ultimate point where it can stop.

Well then, in this immensity of length and breadth and height there flits an infinite quantity of atoms in-numerable, which though separated by void yet cohere together, and taking hold each of another form unions wherefrom are created those shapes and forms of things which you think cannot be created without the aid of bellows and anvils, and so have saddled us with an eternal master, whom day and night we are to fear; for who would not fear a prying busybody of a god, who forsees and thinks of and notices all things, and deems that everything is his concern?

An outcome of this theology was first of all your doctrine of Necessity or Fate, heimarmene, as you termed it, the theory that every event is the result of an eternal truth and an unbroken sequence of causation. But what value can be assigned to a philosophy which thinks that everything happens by fate? it is a belief for old women, and ignorant old women at that. And next follows your doctrine of mantike, or Divination, which would so steep us in superstition, if we consented to listen to you, that we should be the devotees of soothsayers, augers, oracle-mongers, seers and interpreters of dreams. But Epicurus has set us free from superstitious terrors and delivered us out of captivity, so that we have no fear of beings who, we know, create no trouble for themselves and seek to cause none to others, while we worship with pious reverence the transcendent majesty of nature.