Fatherhood is a reality that belongs to the category of relationship. However relationship has to have a real concrete [ontological] basis in the nature of the two things in relation. In physical fatherhood it is man’s biological capacity to cooperate with woman in bringing about conception and his spiritual nature enabling him to educate the child.
In the priest the ontological basis for his supernatural fatherhood is the supernatural sacramental power he receives in priestly ordination. It is this sacramental character that makes him ontologically ( i.e. really and concretely not just symbolically) share in the priesthood of Jesus Christ. Now Jesus Christ became priest through his Incarnation for one purpose: to bring into existence a new humanity, a new race of men with a new supernatural life. Thus Jesus Christ, the Eternal Priest, became the New Adam, the father of a new human family. He who said “I and the Father are one” (Jn.10:30) by liberating man from the power of Satan through his passion and death, fathered sons and daughters of God for eternal life through his passion, death, and resurrection!
Through entrance into the sacred order of the priesthood by ordination the Ignatian is linked with the ancient unbroken line of priests stretching back to the first priests ordained by Jesus Christ, to whom he imparted a participation in his own divine priesthood. On the day of ordination when he rises from his knees a priest rises as a different man, invested with a new quality of soul ‒ the sacramental character – which confers upon him a participation in the eternal priesthood of Jesus Christ. From then on he is empowered to act with the powers of Christ in order to achieve what Christ intended to achieve with his priesthood. Thus, like St. Paul, he can say in a way unique to the priest “It is no longer I who live but Christ who lives in me”(Gal. 2:20). Unique to the priest because he is mystically united to Christ as Head and Spouse of His Mystical Body the Church. His sacramental actions are actions of Christ’s priestly fatherhood bringing undying supernatural life to the souls of men by which they participate in the very life of God himself and thus really become divinized! Thus the priest as Alter Christus (“another Christ”) shares mysteriously in the fatherhood of God. Therefore, in the strict sense, he is really, “biologically” father. It is real, life-giving, “biological” fatherhood because it is about the bringing into existence of a new “bios”[life], a supernatural “bios” – the life the Church calls “sanctifying grace” – that enables the man who receives it to live eternally.
The priest’s fatherhood is “physical” “bios-giving” but it is a “physis” [nature] that is superior to man’s nature. Derived from the priestly sacramental character sealing him indelibly with a new supernatural quality of soul, it has become a new quality of his soul. Thus he can “naturally” procreate supernatural life in souls because of his power for supernatural fatherhood deriving from the sacramental character and he can nourish and educate his supernatural children by the powers for spiritual fatherhood deriving from the special fullness of the gifts of the Holy Spirit received at ordination. When he baptizes he confers supernatural existence. Through the Sacrament of Confession he and he alone in the sacramental economy of salvation restores the divine life to souls dead because of sin, or, if it is a confession of venial sins, he reinvigorates this life grown weak through lesser wounds by applying the fragrant balm of grace.
And – let us think long and hard on this – it is no inferior life! We are talking about the very life of the Godhead who banged out the Big Bang and set the universe in motion! Life that in its present form is a combination of matter and spirit will be destroyed at death but the soul in sanctifying grace will live forever unto total fulfillment and utter happiness. Let us make no mistake about it: it is real life, by comparison with which biological life is a mere shadow, a “ghost”. For it is the perfect life, the life of God himself, the life that is eternally young, undying, holy, untarnished in goodness and purity, devoid of all earthly limitations; a life that is sublime and sheer vitality in comparison with which all human life is a mere distant reflection light years away; it is a life that begins to change man while living on earth but ultimately will transform his whole person in Heaven. As C. S. Lewis stated:
“But what man in his natural condition, has not got is Spiritual life the higher and different sort of life that exists in God. We use the same word life for both: but if you thought that both must therefore be the same sort of thing, that would be like thinking that the ‘greatness’ of space and the `greatness’ of God were the same sort of greatness. In reality, the difference between Biological life and Spiritual life is so important that I am going to give them two distinct names. The Biological sort which comes to us through Nature, and which (like everything else in Nature) is always tending to run down and decay so that it can only be kept up by incessant subsidies from Nature in the form of air, water, food, etc., is Bios. The Spiritual life which is in God from all eternity, and which made the whole natural universe, is Zoe. Bios has, to be sure, a certain shadowy or symbolic resemblance to Zoe: but only the sort of resemblance there is between a photo and a place, or a statue and a man. A man who changed from having Bios to having Zoe would have gone through as big a change as a statue which changed from being a carved stone to being a real man. And that is precisely what Christianity is about. This world is a great sculptor’s shop. We are the statues and there is a rumor going round the shop that some of us are some day going to come to life.” (C. S. Lewis, Mere Christianity)
Indeed God created man for this life: a life that the first human beings received but lost in the Fall but that each man can now regain if he accepts Jesus Christ as Lord and Savior.This life is what Christianity is all about; this is why the Catholic Church exists; this is the life for which the very universe is merely a means to an end. God intends man to be divinized by sharing in the very life of the Blessed Trinity. This is the “anthropic principle” par excellence since everything on earth exists in function of the perfect realities existing in Heaven.
Therefore the priest’s powers of supernatural fatherhood are the very reason for the priesthood and indeed for the Church: to bring man into the new and supernatural life of God himself, to nourish it, defend it, strengthen it, restore it when destroyed, provide the means for growth and finally help the soul cross over the abyss of death to encounter God. “Our parents generate us for the present life, priests for life eternal” ( St. John Chrysostom, De Sacerdotio, 1,3). Beginning with the apostles, priests have been able to say to their supernatural sons and daughters: “Though you have countless guides in Christ, you do not have many fathers. For I begot you in Christ Jesus through the gospel.”(1 Cor 4:15-17). This is the life that the priest is father to in souls! Awesome privilege! Awesome fatherhood!
So when we say that the priest is father supernaturally we are not saying so in any metaphorical, “shadowlands” sense: it is implied in the ontological reality of the sacramental character and the special fullness of the gifts of the Holy Spirit received at ordination. This is the “physical” or “natural” dimension of the priest as father because he is the instrumental cause for this life to reach its maturity in the Christian soul.