From Chapter One, Likings and Loves for the Sub-Human.
How the Need-pleasures foreshadow our Need-loves is obvious enough. In the latter the beloved is seen in relation to our own needs, just as the scullery tap is seen by the thirsty man or the glass of gin by the alcoholic. And the Need-love, like the Need-pleasure, will not last longer than the need. This does not, fortunately, mean that all affections which begin in Need-love are transitory. The need itself may be permanent or recurrent. Another kind of love may be grafted on the Need-love. Moral principles (conjugal fidelity, filial piety, gratitude, and the like) may preserve the relationship for a lifetime. But where Need-love is left unaided we can hardly expect it not to "die on us" once the need is no more. That is why the world rings with the complaints of mothers whose grown-up children neglect them and forsaken mistresses whose lovers' love was pure need -- which they have satisfied. Our Need-love for God is in a different position because our need of Him can never end either in this world or in any other. But our awareness of it can, and then the Need-love dies too. "The Devil was sick, the Devil a monk would be." There seems no reason for describing as hypocritical the short-lived piety of those whose religion fades away once they have emerged from "danger, necessity, or tribulation." Why should they not have been sincere? They were desperate and they howled for help. Who wouldn't?