In the flood of the loss of humanness in our age – including the flow from abortion-on-demand to infanticide and on to euthanasia – the only thing that can stem this tide is the certainty of the absolute uniqueness and value of people. And the only thing which gives us that is the knowledge that people are made in the image of God. We have no other final protection. And the only way we know that people are made in the image of God is through the Bible and in the incarnation of Christ, which we know from the Bible.
If people are not made in the image of God, the pessimistic, realistic humanist is right: the human race is an abnormal wart on the smooth face of a silent and meaningless universe. In this setting, abortion, infanticide, and euthanasia (including the killing of mentally deranged criminals, the severely handicapped, or the elderly who are an economic burden) are completely logical… Without the Bible and without the revelation in Christ (which is only told to us in the Bible) there is nothing to stand between us and our children and the eventual acceptance of the monstrous inhumanities of the age.
Francis Schaeffer (with C Everett Koop), “Whatever Happened to the Human Race?”