Three is the essential numeric value of love. Where there is only one person, love cannot occur. Where there are two, each is the sole recipient of the other’s attention, giving place for self-absorption. But the moment there are three, each recipient of any one’s love must also humbly defer attention to the third party, and each one is the third party to the other two. Pure selflessness can now occur by virtue of the fact that each one must love and be loved with both an exclusive and a divided interest.
If God’s essential identity is traceable to a solitary selfhood—which would be the case if Jesus in any sense had a point of beginning, and if the Holy Spirit does not eternally exist with distinct personhood—then love is not essential to God’s nature. Said more simply, if Father, Son and Holy Spirit are not eternally co-existent, it cannot be said with any coherence that “God is love.”
The pure biblical genius of identifying God as a triune fellowship rather than as an absolute singularity or even as a dualism, is convincing evidence that the Bible is, in fact, the revelation of the one and only true God, whose essential nature is love.