Book XI · 17
Consider whence each thing is come, and of what it consists, and into what it changes, and what kind of a thing it will be when it has changed, and that it will sustain no harm.
Think whence each thing has come, of what it is built up, into what it changes, what it will be when changed; and that it cannot take any harm.
Marcus Aurelius, Meditations XI.17. Translated by George Long (1862). The Stoic Library.