At the center of Christian faith is the doctrine of the Trinity, namely, that we believe in one God who is Three Persons. This truth shapes all the other teachings of the Church, including the teachings on abortion. Let's look first at some of the Scriptural teachings on the Trinity.
The New Testament reveals the fact that the Persons of the Trinity have an intimate sharing of life with each other, and that furthermore, that life is passed on to us in a manner in some way comparable to what happens in the Trinity. In John 17: 20-23 we read, "I pray not only for them, but also for those who will believe in me through their word, so that they may all be one, as you, Father, are in me and I in you, that they also may be one in us, that the world may believe that you sent me. And I have given them the glory you have given me, so that they may be one, as we are one, I in them and you in me, that they may be brought to perfection as one, that the world may know that you sent me, and that you loved them even as you loved me."
The Trinity exhibits the ultimate realities of union and self-giving, which then, not by necessity but by God’s free decision, overflow into our lives. We are caught up in the life of the Trinity, the life of Grace. The Father loves us as He loves the Son. The Son commands us to love one another as He loves us (see Jn. 15: 12).
Just as the Father shows Himself to the Son, the Son reveals the Father to us. We read in Matthew 11: 27: "All things have been handed over to me by my Father. No one knows the Son except the Father, and no one knows the Father except the Son and anyone to whom the Son wishes to reveal Him." This knowledge, of course, is the eternal life (see Jn. 17: 3) which is Christ Himself.
The Lord makes the same connection when He speaks of the Eucharist in John 6: 57: "Just as the living Father sent me and I have life because of the Father, so also the one who feeds on me will have life because of me."
The Holy Spirit is sent by both the Father and the Son. "And I will ask the Father, and he will give you another Advocate to be with you always, the Spirit of truth" (Jn. 14: 16-17). "If I do not go, the Advocate will not come to you. But if I go, I will send him to you" (Jn. 16: 7). He is sent by the Father and the Son because He proceeds from them both. The giving of the Spirit to us in history reflects the Trinitarian life of God beyond history.
The link here with the abortion struggle is this: We do not find fulfillment unless we give ourselves away in love. The very existence of the Persons in the Trinity is defined by their mutual self-giving. The same is true, in an analogous way, with us. To see the abortion debate as simply a conflict between the rights of the mother and the rights of the child is to underestimate the depth of this controversy. The abortion debate goes deeper. It is about the question, "Can mother and child find their fulfillment apart from each other?"
Some claim, "Abortion is my right because I have the right to fulfill myself in this society." If one chooses not to marry and raise a family, that is fine. But in that case, there is still no fulfillment unless the person's life is spent in self-giving, whether in service to society or to the Church. Moreover, whether married or not, when a woman carries a child within her, she now faces the question, "Can I really find fulfillment by pushing another human being out of the way?' Our answer is no. We never find fulfillment by pushing another person out of the way. We find it when we push ourselves out of the way.
It is obvious that the preborn child needs the mother to survive, at least for a time. What we also need to draw more attention to is the fact that the mother, as all of us, need to give ourselves away to the child and for the child, not just as a charity or a good deed, but as an essential condition of our own fulfillment. To be fully human involves accepting the call to be fruitful, to give life, in one form or another. After all, human beings were created by the Trinity!