God's law, in both Old and New Testaments, teaches us how to behave as ones who bear God's image as well as how to treat other image-bearers. This is the biblical pro-life ethic.
In its simplest form, we could call it "brother-keeping." We know that the first murderer asked, "Am I my brother's keeper?" Cain hoped God would overlook the loss of Abel, but God was fully aware. Cain didn't know that Abel's blood cried out to God from the ground (Genesis 4:9-10).
In Genesis 9:5-6, Noah and his sons were told
Surely for your lifeblood I will demand a reckoning; from the hand of every beast I will require it, and from the hand of man. From the hand of every man’s brother I will require the life of man.
Whoever sheds man’s blood,
By man his blood shall be shed;
For in the image of God He made man.
Here we see that one aspect of brother-keeping is avenging a brother's murder. Capital punishment grew out of this principle. The death penalty does not violate the sanctity of human life unless it is carried out unjustly.
Passages such as Psalm 10:8-14, Proverbs 24:10-12, Luke 11:50-51, and Revelation 6:9-11 assure us that God keeps track of every human life lost and avenges their deaths when we don't. Just as He knows when a sparrow falls, and numbers the hairs of our heads, so He takes notice when His image-bearers are killed or mistreated (Luke 12:6-7). As with the murder of Abel, blood that is not atoned or avenged is said to stain the land, particularly the land of Israel (Numbers 35:33-34).
Related Bible study—Murder Mystery: The Case of the Unknown Killer
Murder is the most extreme failure of brother-keeping, but there are many ways to fail in this regard, as is borne out in so many passages in the Law of Moses and the Prophets (see references below).
Old and New Testaments teach us to love our neighbors, but like the lawyer in Luke 10, we're prone to limiting our responsibility to people from our own tribes or nations. Jesus doesn't let us off easily. He takes brother-keeping and neighbor-loving to another level by telling us to also love our enemies! (Luke 6:27-36)
NEXT > Applying the pro-life ethic
PREVIOUS > Why life matters