Why we march
So, why do we march? You would undoubtedly get a variety of answers to this question from marchers, but the main point is to witness to the sanctity of human life. God has given an immeasurably beautiful gift with each life that He has created. He has given a part of Himself with every new creation, for He Himself is Life. Because God creates every male and female in His own image and likeness, every human life is sacred and has great dignity.
While we lost it due to original sin, God restored human dignity and raised it when He took on human flesh in the person of Jesus Christ. In Christ, human and divine life become one. Every human life is in Christ, and Christ is in every human life, especially the most vulnerable persons ("least of my brethren" - Matthew 25). Christ is in the embryo, the baby in the womb, the poor, the handicapped, the homeless, the lonely, the victim of violence, the suffering, the elderly, et al. An attack on any human person is an attack on Christ himself.
The March for Life is a witness to the dignity and sanctity of all human life, especially for those persons who have been attacked (over 46,000,000 by abortion in the U.S. since '73). It is a witness to Christ, preaching his Gospel of Life. It is a witness to Truth, exposing the lies of the culture of death. It is a witness to Hope, believing that the culture of life will return again in this great country of ours. It is a witness to Love, sacrificing parts of our own lives for the sake of Life.