Shorter Catechism Q. 69. What is forbidden in the sixth commandment? A. The sixth commandment forbiddeth the taking away of our own life, or the life of our neighbor unjustly, or whatsoever tendeth thereunto.
Commentary: The sixth commandment forbids “the taking away of our own life,” that is, suicide. Some may defend suicide on the basis that people have a right to do what they want with their own life. Their life, however, is not their own, but God’s. He is the Lord and he alone has the prerogative to take away life. Since he forbids it, suicide is (self) murder.
The sixth commandment also forbids “the taking away of…the life of our neighbor unjustly.” This would include killing the unborn, the sick, the elderly, the disabled and those who ask to be put to death (assisted suicide). It does not include the State killing criminals guilty of a capital crime, killing in times of war and killing in self-defense. Hence, the catechism adds the word “unjustly.”
The sixth commandment forbids anything that would diminish a person’s life: “or whatsoever tendeth thereunto.” We, therefore, break this commandment when we indulge in angry, revengeful, hateful, abusive thoughts, words, and actions.
WLC 136 provides a detailed list of what this commandment forbids: “The sins forbidden in the sixth commandment are, all taking away the life of ourselves, or of others, except in case of publick justice, lawful war, or necessary defence; the neglecting or withdrawing the lawful and necessary means of preservation of life; sinful anger, hatred, envy, desire of revenge; all excessive passions, distracting cares; immoderate use of meat, drink, labour, and recreations; provoking words, oppression, quarrelling, striking, wounding, and whatsoever else tends to the destruction of the life of any.”