In Introduction to Christianity, Joseph Ratzinger explains how the dogma of the Trinity emerged from early Christian experience.
The apostles discovered that “in Jesus Christ one meets a man who at the same time knows and professes himself to be the Son of God. One finds God in the shape of the ambassador who is completely God and not some kind of intermediary being, yet with us says to God ‘Father'” (115).
Ratzinger - Paradox - Hand - Man - God
Ratzinger calls it a “paradox”: “one the one hand this man calls God his Father and speaks to him as to someone else facing him; if this is not to be a piece of empty theatricality but truth . . . then Christ must be someone other than this Father to whom he speaks and to whom...