“You wish to hear from me why and in what manner God should be loved. I answer then: the reason for loving God is God [himself]; and there should be no measure [of that love]. Is that enough to say about the matter? For a wise man it most probably is, but I am a debtor to the unwise also. And though I may have said enough for those with understanding, I must have due regard for others too. For those less apt, then, I gladly will explain what I have said more fully, if not with greater depth.
I might have said there was a twofold reason why we are to love God [solely] for himself. Firstly, nothing is more just, and secondly, nothing is more profitable. The question ‘Why should God be loved?’ includes both of these, for it may mean either ‘What is his claim upon our love?’ or ‘What benefit shall we derive from loving him?’. My former answer stands in either case: there is no other worthy cause for loving God except himself.
And firstly, as to his claim upon our love, he surely merits much from us who gave himself to us, unworthy as we were: what better gift could he have given than himself? If, then, it is his claim we have in mind when asking ‘Why should God be loved?’, the first and foremost answer is, ‘Because he first loved us’ (1 Jn. 4:19). Most plainly is he worthy of being loved in return by us, especially if we consider who he is who thus bestows his love on us, who the objects of it are, and how great it is. For who is he, save he whom every soul confesses, ‘Thou art my God, my goods are nothing unto Thee’ (Ps. 16:2). His is indeed that majestic love which ‘seeketh not its own’ (1 Cor. 13:5). But who are they to whom he shows this selfless love? ‘When we were enemies,’ says the Apostle, ‘we were reconciled to God’ (Rom. 5:10). God, then, has loved us freely, while we were enemies. How much has he loved us? John says: ‘God so loved the world the world that he gave his only begotten Son’ (Jn. 3:16). ‘He that spared not his own Son,’ says Paul, ‘but delivered him up for us all’ (Rom. 8:32). The Son, moreover, tells us of himself, ‘Greater love hath no man than this, that a man lay down his life for his friends’ (Jn. 15:13). This is the claim that the Just One has on sinners, the Highest on the lowest, and he who is Almighty on the weak. You say, perhaps, Yes, that is true of men, but with the angels it is otherwise. That I admit: the angels had not our human need. For the fact is that he who helped man in his misery kept them from falling into such a plight at all; and he whose love gave men the means to leave their lost estate, by a like love preserved the angels from sharing in our fall.”
– Bernard of Clairvaux (1090-1153), De diligendo Deo, Chapter 1