Meditation 8.59-61
Marcus AureliusMeditationsBook 8.59
59. Men have come into the world for the sake of one another. Either instruct them then or bear with them.
60. An arrow's path and the mind's path are different. Nevertheless, both when it is on its guard and when it revolves round a subject of inquiry, the path of mind is none the less direct and upon its object.
61. Enter into the governing self of every man and permit every other man to enter into your own.