If God Were Single
Tuesday, October 30, 2012 at 7:00AM 
Two reasons why it matters that God exists as Trinity:
If God was not a Father, he could never give us the right to be his children. If he did not enjoy eternal fellowship with his Son, on has to wonder if he would have any fellowship to share with us, or if he would even know what fellowship looks like. If, for example, the Son was a creature and had not eternally been “in the bosom of the Father,” knowing him and being loved by him, what sort of relationship with the Fater could he share with us? If the Son himself had never been close to the Father, how could he bring us close?
If God was a single person, salvation would look entirely different. He might allow us to live under his rule and protection, but at an infinite distance, approached perhaps through intermediaries. Her might even offer forgiveness, but he would not offer closeness. And, since by definition he would not be eternally loving, would he deal with the price of sin himself and offer that forgiveness for free? Most unlikely. Distant hirelings we would remain, never to hear the Son’s golden words to his Father: “You have loved them even as you have loved me.”
What’s more,
if God is a single person, and has always been alone, why should he speak? In the loneliness of eternity before creation, who would he have spoken to? And why would he start now? The habit of keeping himself to himself would run deep. Such a God would be far more likely to remain unknown.
Quoting from Delighting in the Trinity: An Introduction to the Christian Faith by Michael Reeves.
