Some things are hurrying to come into being, others are hurrying to be gone, and part of that which is being born is already extinguished. Flows and changes are constantly renewing the world, just as the ceaseless passage of time makes eternity ever young. In this river, then, where there can be no foothold, what should anyone prize of all that races past him? It is as if he were to begin to fancy one of the little sparrows that fly past - but already it is gone from his sight. Indeed this is the nature of our very lives - as transient as the exhalation of vapour from the blood or a breath drawn from the air. No different from a single breath taken in and returned to the air, something which we do every moment, no different is the giving back of your whole power of breathing - acquired at your birth just yesterday or thereabouts - to that world from which you first drew it.
Death should constantly be before our eyes. Many avoid the thought of death. But those same people love the change in seasons, especially when summer gives way to autumn or when autumn gives fully to winter. As Marcus notes, change is constant and we should love it.
We breathe in, we breath out - no great matter to us.
We dip our hand into the river and no great matter to see some water or debris touch our hand and flow downstream.
We watch birds flutter about trees; they land and disappear as quickly as they came - no great matter.
In the vast flow of eternity, our first breath to our last breath is just as quick as a single inhalation and exhalation. Neither should upset us much at all.
(see also Citadel p. 171)