Christian opposition to abortion is based on a number of sources. The Didache, a short early Christian treatise, specifically prohibits abortion. The Bible, unlike the Didache, makes no specific mention of abortion, although it does mention unborn life several times. For example, Luke 1: 44 cites Elizabeth exclaiming to the Virgin Mary, "Behold, when the voice of your greeting came to my ears, the babe in my womb (John the Baptist) leaped for joy". Jeremiah 1: 4-5, retelling God's appointing of Jeremiah to be a prophet, says: "Before I formed you in the womb I knew you, and before you were born I consecrated you".
The Catholic Church teaches that "abortion is a grave sin against the natural law."[11] It believes that human life is sacred, and begins at conception. Under this view, abortion is equivalent to murder, and there are no permissible exceptions. When the life of the woman is in jeopardy, it is permissible to obtain life-saving treatment which may have the secondary effect of killing the fetus, but no direct action may be taken against the fetus/embryo itself, and all life-sustaining options must be exhausted. (An example is chemotherapy treatment for a pregnant woman with uterine cancer.) It also ascribes to a Consistent Life Ethic: euthanasia, the death penalty, unjust war, embryo research, in vitro fertilization (which involves discarded embryos), artificial contraception (of which some methods may prevent implantation of a zygote in the uterine lining), and abortion are all condemned as violence. Church law provides that anyone who directly participates in an abortion is automatically excommunicated (provided they are aware of this penalty at the time of the act)[12] A valid sacramental confession remits this penalty. In accord with its opposition to abortion, the Catholic Church provides support to pregnant women in "crisis pregnancies," as well as to low income families.