Meditations by Marcus Aurelius Book 4 Page 6

this kind of retiring of thyself, to this little part of thyself; and above all things, keep thyself from distraction, and intend not anything vehemently, but be free and consider all things, as a man whose proper object is Virtue, as a man whose true nature is to be kind and sociable, as a citizen, as a mortal creature.

Among other things, which to consider, and look into thou must use to withdraw thyself, let those two be among the most obvious and at hand. One, that the things or objects themselves reach not unto the soul, but stand without still and quiet, and that it is from the opinion only which is within, that all the tumult and all the trouble doth proceed. The next, that all these things, which now thou seest, shall within a very little while be changed, and be no more: and ever call to mind, how many changes