'God is love' (1 John 4.8): this verse must be the most quoted in the New Testament. Pope Benedict XVI took it as the theme of his first encyclical, Deus caritas est (25 December 2005). He chose it because it carries a message 'both timely and significant', as he says, 'in a world where the name of God is sometimes associated with vengeance or even a duty of hatred and violence'. He doesn't spell out that dark, enigmatic thought.
'God is love' is not reversible, as if Christians might just as well say 'love is God'. That would express what people have explicitly believed in some ancient religions. It might fit well enough with what people in our own society seem to assume, judging by their leisure activities. Venus, the Roman goddess of love, was celebrated in pagan religious festivals, before and after New Testament times. Today, with so much pornography available, Venus still holds sway, in more elusive and seedier guises.
Apart from all that, the word 'love' is so sentimentalised in pop culture - as 'lurv' - that it would almost be like teaching a foreign language to explain what Saint John meant. For that matter, in the vernacular of our Catholic liturgy, let alone in Sunday homilies (!), the word 'love' can easily sound so bland or fuzzy, functioning as a catch-all for every pious exhortation, or as a substitute for testing reflection, that we are not in a strong position to deplore the ignorance of our neighbours.
The word that Saint John uses is 'agapè': a word that has never been anglicized and from which no English word is derived. (Theologians who refer to Christian love as 'agapetic' don't expect the word to catch on any time soon.) In the secular Greek of the day, the verb was used quite colourlessly: 'to like'. The New Testament writers, Saint Paul as well as Saint John, seem to have deliberately adopted this rather neutral word. It is used, as they presumably knew, in the Greek version of the Old Testament, for the kind of love which cares for others, to the extent of being ready to make sacrifices for their sake. Paul and John take the word up to designate the new way of loving which Jesus inaugurated.
This was not any kind of love that originates in the human heart, whether the various kinds that reach out to embrace spouse, parents, children, and friends, or, at a different level, the kind of love people have for sport or music or their native land. This other kind of love consists in this, 'not that we have loved God, but that He loved us and sent His Son as an atonement for our sins'. This is the love which older translations refer to as 'charity' - another word that has lost most of its New Testament meaning in ordinary conversation.
There is of course nothing intrinsically wrong with any of these natural loves - to the contrary; though, needless to say, they are vulnerable to many different kinds of distortion, some much more serious than others. It's one thing, however, to maintain that the various kinds of love that come naturally may be healed in the light of the divine gift of charity. It's another matter to set 'eros' and 'agapè' over against each other, as if our natural loves were always intrinsically selfish and possessive, and needing to be thwarted and even replaced by some supposedly otherworldly kind of love. 'Were this antithesis to be taken to extremes', the Pope writes, 'the essence of Christianity would be detached from the vital relations fundamental to human existence, and would become a world apart, admirable perhaps, but decisively cut off from the complex fabric of human life'.
To the contrary, granting that 'even if eros is at first mainly covetous', he contends that 'in drawing near to the other, it is less and less concerned with itself, increasingly seeks the happiness of the other, is concerned more and more with the beloved' - to the extent that, as the Pope insists, there is an 'intrinsic link' between 'the reality of human love' and 'the love which God mysteriously and gratuitously offers to us'. But we'd need to read the Encyclical to get much further than that