"God is faithful, who has called you into fellowship with his Son, Jesus Christ our Lord." (1Corinthians 1:9 NIV)
The doctrine of the Trinity is not some philosophical concept thought up at the Council of Nicea in 325 AD to give the Church of God something to argue about. It would probably be simpler and more appealing to be like the Moslems or Jews and have an uncomplicated solitary Being to run everything. Yet we do not have to go very far to see interaction between different persons of the Godhead in the New Testament (cf. "Defense" 2. Is There a God?). As I explained here, philosophically, in order for God to have the characteristic of "love" He would have to have this for all eternity. However, since love as a verb requires an object; who would be that object before creation? Fellowship between God and man makes sense only if there is a plurality within the Godhead. Even the Old Testament, if you look with an open mind, shows this same interaction amongst the Godhead as I have pointed out in my newest addition to Defense.
God wants to love us. Koinonia, the Greek word for fellowship, also means participation. In 2 Peter 1:4, we are told that our destiny is participation in the Divine Nature. We are intimately in conversation with a widening circle that starts with the Trinity and includes us.
The Father, Son and Holy Spirit had complete and perfect fellowship. The Trinity had no need to widen the circle of fellowship but for “pleasure” (chara) we were invited into the inner sanctum of heaven at a terrible cost—the cross. God has called us to continue to widen the circle and invite others. But to do so is also at a costloss of friendship with the world, and a wonderful reward—intimacy with God the Father, God the Son, and God the Holy Spirit forever.
Pray: "Dearest Lord, Thank you for inviting us into the Fellowship."