The First Things First Principle

C.S. Lewis:

The woman who makes a dog the centre of her life loses, in the end, not only her human usefulness and dignity but even the proper pleasure of dog-keeping.
The man who makes alcohol his chief good loses not only his job but his palate and all power of enjoying the earlier (and only pleasurable) levels of intoxication.
It is a glorious thing to feel for a moment or two that the whole meaning of the universe is summed up in one woman—glorious so long as other duties and pleasures keep tearing you away from her. But clear the decks and so arrange your life (it is sometimes feasible) that you will have nothing to do but contemplate her, and what happens?
Of course this law has been discovered before, but it will stand re-discovery. It may be stated as follows: every preference of a small good to a great, or partial good to a total good, involves the loss of the small or partial good for which the sacrifice is made.
. . . You can’t get second things by putting them first. You get second things only by putting first things first.

—C.S. Lewis, “First and Second Things,” in God in the Dock: Essays on Theology and Ethics (Eerdmans, 1994), p. 280.
{HT: Joel Willitts}
This, of course, is reminiscent of Lewis’s comment in a letter to Dom Bede Griffiths (April 23, 1951):

“Put first things first and we get second things thrown in: put second things first and we lose both first and second things. We never get, say, even the sensual pleasure of food at its best when we are being greedy.”