Marcus Aurelius
Meditations 7.30
Direct thy attention to what is said. Let thy understanding enter into the things that are doing and the things which do them.
Marcus Aurelius, Meditations 7.30, translated by George Long
Do thy utmost to keep up with what is said. Let thy mind enter into the things that are done and the things that are doing them.
Marcus Aurelius, Meditations 7.30, translated by C. R. Haines