When we think of the love of God, we generally don't think of it as a difficult doctrine. Whe we think of God's sovereignty or wrath we do, but not his love. The title of this blog is stolen from an incredible little book by DA Carson. In it, he explores briefly five ways in which the Bible speaks of the love of God...
First, Carson points out that there has been an eternal love within the Godhead. The Father has eternally loved the Son. The Son has eternally loved the Father. I think this is actually essential to understanding the statement "God is love". If God had eternally existed in singularity instead of plurality, then he would have had no object to love, at least not in any kind of reciprical relationship. He would have then needed to create out of some deficiency - he would have needed to create so that he could be in relationship and express his love. This is not, however, the case. He dwelled for an eternity in relationship with himself, in Trinity. And we was fine. He wasn't lonely or needy. So he didn't create out of lack, but out of overflow.
Secondly, Carson reminds us that the Bible speaks of God's providential love to all his creation. Matthew 6 gives us wonderful pictures of a loving Creator caring for his world in wonderful ways - clothing the lilies, feeding the birds, etc.
Third, there is a sense, Carson reminds us, in which God showed his love to the whole world through the gift of his Son, Jesus Christ. John 3:16 says that "God so loved the world, that he gave his only son". This is the most incredible display of love ever made. In fact, as Bob mentioned, we can't fully know what love is apart from knowing this love.
Fourth, there is a strong, chosing, saving love that God shows for his elect. To those whom he has chosen, he has not just made the offer of salvation, but has actually saved them - not because they were great or worthy, but out of his grace and love (Deuteronomy 7:7-8). At this point some may object to the discriminating nature of God's love - he loves whom he wants to. But, let me argue that we should allow God the same freedoms with his love that we expect for ourselves - the freedom to love people in different ways. I certainly love my sister, but I also certainly love her differently than I love my wife (otherwise, it would just be weird and wrong!). God, as we have already said, loves his creation, all of it. Yet, it also true that God loves some people in particularly strong way, and acts on it by saving them.
Finally, the Bible does seem to teach that there is a kind of love that is conditioned upon obedience. Frankly, this one makes me the most uncomfortable, but it shouldn't. Will I ever be out of God's love? In one sense, no. I will never loose my salvation - I have experienced Gods saving loving and that will never be taken away. Yet, I can grow into deeper experiences of God's love as I committ to obey and walk daily with Christ, choosing him over the pleasures of sin. Jesus says in John 15 "if you obey my commands, you will remain in my love, just as I have obeyed the Father's commands and remain in his love".
So, as you see, the doctrine of the love of God isn't as simple as you might have thought. Yet I think because it isn't so simple, but complex, it is all the more beautiful.