Epictetus 3.22.40-44
In what kind of subject-matter for life ought one to seek serenity, and freedom from restraint? In that which is slave, or in that which is free?" "In the free." "Is the paltry body which you have, then, free or is it a slave?" "We know not." "You do not know that it is a slave of fever, gout, ophthalmia, dysentery, a tyrant, fire, iron, everything that is stronger?" "Yes, it is their servant." "How, then, can anything that pertains to the body be unhampered? And how can that which is naturally lifeless, earth, or clay, be great or precious? What then? Have you nothing that is free?" "Perhaps nothing." "And who can compel you to assent to that which appears to you to be false?" "No one." "And who to refuse assent to that which appears to you to be true?" "No one." "Here, then, you see that there is something within you which is naturally free. But to desire, or to avoid, or to choose, or to refuse, or to prepare, or to set something before yourself—what man among you can do these things without first conceiving an impression of what is profitable, or what is not fitting?" "No one." "You have, therefore, here too, something unhindered and free. Poor wretches, develop this, pay attention to this, seek here your good."