Think, often, of how swiftly all things pass away and are no more—­the works of Nature and the works of man.  The substance of the Universe—­matter—­is like unto a river that flows on forever.  All things are not only in a constant state of change, but they are the cause of constant and infinite change in other things.  Upon a narrow ledge thou standest!  Behind thee, the bottomless abyss of the Past!  In front of thee, the Future that will swallow up all things that now are!  Over what things, then, in this present life, wilt thou, O foolish man, be disquieted or exalted—­making thyself wretched; seeing that they can vex thee only for a time—­a brief, brief time! (Book v., Sec.23.)

THE PERFECT LIBERTY OF THE GOOD MAN

Peradventure men may curse thee, torture thee, kill thee; yet can all these things not prevent thee from keeping at all times thy thoughts pure, considerate, sober, and just.  If one should stand beside a limpid stream and cease not to revile it, would the spring stop pouring forth its refreshing waters?  Nay, if such an one should even cast into the stream mud and mire, would not the stream quickly scatter it, and so bear it away that not even a trace would remain?  How then wilt thou be able to have within thee not a mere well that may fail thee, but a fountain that shall never cease to flow?  By wonting thyself every moment to independence in judgment, joined together with serenity of thought and simplicity in act and bearing. (Book viii., Sec.51.)

THE HARMONY AND UNITY OF THE UNIVERSE

O divine Spirit of the Universe, Thy will, Thy wish is mine!  Calmly I wait Thy appointed times, which cannot come too early or too late!  Thy providences are all fruitful to me!  Thou art the source, Thou art the stay, Thou art the end of all things.  The poet says of his native city, “Dear city of Cecrops”; and shall I not say of the Universe, “Beloved City of God”? (Book iv., Sec.23.)

Either there is a predestined order in the Universe, or else it is mere aggregation, fortuitous yet not without a certain kind of order.  For how within thyself can a certain system exist and yet the entire Universe be chaos?  And especially when in the Universe all things, though separate and divided, yet work together in unity? (Book iv., Sec.27.)

Think always of the Universe as one living organism, composed of one material substance and one soul.  Observe how all things are the product of a single conception—­the conception of a living organism.  Observe how one force is the cause of the motion of all things:  that all existing things are the concurrent causes of all that is to be—­the eternal warp and woof of the ever-weaving web of existence. (Book iv., Sec.40.)

THE CONDUCT OF LIFE