We are all working together to one end, some with knowledge and design, and others without knowing what they do; as men also when they are asleep, of whom it is Heraclitus, I think, who says that they are labourers and co-operators in the things which take place in the universe. But men co-operate after different fashions: and even those co-operate abundantly, who find fault with what happens and those who try to oppose it and to hinder it; for the universe had need even of such men as these. It remains then for thee to understand among what kind of workmen thou placest thyself; for he who rules all things will certainly make a right use of thee, and he will receive thee among some part of the co-operators and of those whose labours conduce to one end. But be not thou such a part as the mean and ridiculous verse in the play, which Chrysippus speaks of.
The parts of the whole, everything, I mean, which is naturally comprehended in the universe, must of necessity perish; but let this be understood in this sense, that they must undergo change. But if this is naturally both an evil and a necessity for the parts, the whole would not continue to exist in a good condition, the parts being subject to change and constituted so as to perish in various ways. For whether did nature herself design to do evil to the things which are parts of herself, and to make them subject to evil and of necessity fall into evil, or have such results happened without her knowing it? Both these suppositions, indeed, are incredible.