Meditations 4.1

That which rules within, when it is according to nature, is so affected with respect to the events which happened, that it always easily adapts itself to that which is possible and is presented to it. For it requires no definite material, but it moves towards its purpose, under certain conditions, however; and it makes a material for itself out of that which opposes it, as fire lays hold of what falls into it, by which a small light would have been extinguished; but when the fire is strong, it soon appropriates to itself the matter which is heaped on it, and consumes it, and rises higher by means of this very material.

Marcus Aurelius, Meditations 4.1, translated by George Long

That which holds the mastery within us, when it is in accordance with Nature, is so disposed towards what befalls, that it can always adapt itself with ease to what is possible and granted us. For it is wedded to no definite material, but, though in the pursuit of its high aims it works under reservations, yet it converts into material for itself any obstacle that it meets with, just as fire when it gets the mastery of what is thrown in upon it. A little flame would have been stifled by it, but the blazing fire instantly assimilates what is cast upon it and, consuming it, leaps the higher in consequence.

Marcus Aurelius, Meditations 4.1, translated by C. R. Haines