Part Four – The Incarnation of God the Son
Respecting this great mystery, Catholics believe that the Holy Trinity, out of infinite mercy, decreed to provide for us a Redeemer who could suffer, and suffer as an individual of the human race, and at the same time, be in Himself so exalted as to be able to give infinite value to His sufferings; because sin, being an offence against the infinite majesty of God, could only be atoned for by an expiation of infinite value.
To accomplish this end, God the Son, the second Person of the Holy Trinity, the Eternal Word, chose the Blessed Virgin Mary of Nazareth to become His Mother, and on receiving her consent, He, by the supernatural agency of the Holy Spirit, took human flesh from her, and thus became man, and His Holy Name is JESUS CHRIST.
By becoming man the Eternal Word did not law aside His Divine Nature, but remaining what He had ever been from all eternity, took upon Himself human nature without a human personality, so that from the first moment of His Incarnation there was in Him, and there ever will be, not one only but two natures, the Divine and the human, united in His Divine Personality, the Person of God the Son.
The Divine nature of Jesus is one and the same as that of the Eternal Father and of the Holy Spirit, and His human nature is in all things like ours, sin and tendency to sin excepted. He is equal to the Father as to His Godhead, and less than the Father as to His Manhood.
Our Lord Jesus Christ suffered and died in His human nature on Mount Calvary, and thereby effectually interposed His atonement between His Eternal Father and man, and thus made a plentiful expiation and paid a full ransom to the Eternal Justice for the sins of the whole world.