Peter Kreeft

If God is not a Trinity, God is not love. For love requires three things: a lover, a beloved, and a relationship between them. If God were only one person, he could be a lover, but not love itself. The Father loves the Son and the Son loves the Father, and the Spirit is the love proceeding from both, from all eternity. If that were not so, then God would need us, would be incomplete without us, without someone to love. Then his creating us would not be wholly unselfish, but selfish, from his own need.