Life is to be protected from the moment of concpetion to natural death. Abortion ends the life of a human being by artificial, human means. Not only does abortion end the life of a developing human being, but hurts the mothers physically and they and the fathers and all affiliated with the abortion emotionally and spiritually.
The fifth commandment states:
"Thou shall not kill".
God commands us to not kill so that His creation may say an abundant "Yes!" to life as did Mother Mary. By saying, "Yes!," we not only allow human beings to live, but we allow God's will to live through them.
"Human life is sacred because from its beginning it involves the creative action of God and it remains for ever in a special relationship with the Creator, who is its sole end. God alone is the Lord of life from its beginning until its end: no one can under any circumstance claim for himself the right directly to destroy an innocent human being." (CCC, no. 2258)