Love is a central theme of Christianity. God loves us, and we love Him and each other as a result. In fact, the Bible teaches that God IS love.
Writing a definition for God is inherently difficult, and problematic. There are two main problems with each attempt to define God. The first problem is that we only know what He has revealed to us, so any definition will necessarily be incomplete. The second problem is that while we can use words to describe God, none of those words can help us actually understand Him. Still, that doesn’t mean we shouldn’t try.