52 Amid these irreverent and ill-grounded theories the faith of the Church, inspired by the teaching of the Apostles, has recognised a birth of Christ, but no beginning. It knows of the dispensation, but of no division: it refuses to make a separation in Jesus Christ; whereby Jesus is one and Christ another; nor does it distinguish the Son of Man from the Son of God, lest perhaps the Son of God be not regarded as Son of Man also. It does not absorb the Son of God in the Son of Man; nor does it by a tripartite belief tear asunder Christ, Whose coat woven from the top throughout was not parted, dividing Jesus Christ into the Word, a body and a soul; nor, on the other hand, does it absorb the Word in body and soul. To it He is perfectly God the Word, and perfectly Christ the Man. To this alone we hold fast in the mystery of our confession, namely, the faith that Christ is none other than Jesus, and the doctrine that Jesus is none other than Christ.
Source: On the Trinity (New Advent)