Meditations, Book 7, Section 8

Marcus Aurelius — The Emperor

For a thinking person, the same action is both natural and reasonable.

Straight by itself, not made straight.

Just as different parts work together in one body, thinking people are like parts of one larger body that is spread out. We are all made for one shared purpose. You will understand this better if you often tell yourself: I am a member of the whole community of thinking beings. But if you say I am just a part, you do not yet truly love people from your heart. The joy you feel when you do good for others is not yet based on real understanding of how things work. You do it simply because it seems right and proper. You do not yet see that when you help others, you are helping yourself.

Marcus Aurelius — The Emperor Original

To a reasonable creature, the same action is both according to nature, and according to reason.

Straight of itself, not made straight.

As several members in one body united, so are reasonable creatures in a body divided and dispersed, all made and prepared for one common operation. And this thou shalt apprehend the better, if thou shalt use thyself often to say to thyself, I am μέλος, or a member of the mass and body of reasonable substances. But if thou shalt say I am μέρος, or a part, thou dost not yet love men from thy heart. The joy that thou takest in the exercise of bounty, is not yet grounded upon a due ratiocination and right apprehension of the nature of things. Thou dost exercise it as yet upon this ground barely, as a thing convenient and fitting; not, as doing good to thyself, when thou dost good unto others.