‘You shall not kill! (That is to say, you shall not unrighteously harm or hurt or put anyone to death)! Exodus 20:13.
Calvin remarks in his Institutes II:8:7-9 & 39-40: “We are following Christ, the best Interpreter of the Law (Matthew 5:22,38-44). The Pharisees having instilled into the people the erroneous idea that the Law was fulfilled by every one who did not in external act do anything against the Law — He pronounces this a most dangerous delusion, and declares…that hatred of a brother is murder!
“‘Whosoever is angry with his brother without a cause, shall be in danger of the judgment!’ Whosoever by a whispering or murmuring gives indication of being offended, ‘shall be danger of the Council!’ Whosoever by reproaches and evil-speaking gives way to open anger, ‘shall be in danger of hell-fire!’….
“To despise and rebel against…persons, is offensive to Him…. The Commandment ‘You shall not kill!’ — the generality of men will merely consider as an injunction to abstain from all injury and all wish to inflict injury…. It moreover means that we are to aid our neighbour’s life by every means in our power…. God forbids us to injure or hurt a brother, because He would have his life to be dear and precious to us…. Therefore, when He so forbids, He at the same time demands all the offices of charity which can contribute to his preservation….
“Since the Lord had bound the whole human race by a kind of unity, the safety of all ought to be considered as entrusted to each…. All violence and injustice and every kind of harm from which our neighbour’s body suffers, is prohibited…. We are required faithfully to do what in us lies to defend the life our neighbour; to promote whatever tends to his tranquillity; to be vigilant in warding off harm; and, when danger comes, to assist in removing it….
“This Commandment…requires a sincere desire to preserve our brother’s life. The hand indeed commits the murder — but the mind, under the influence of wrath and hatred, conceives it. How can you be angry with your brother, without passionately longing to do him harm?… ‘Whosoever hates his brother, is a murderer’ (First John 3:15)….
“Man is both the image of God, and our flesh. Therefore, if we would not violate the image of God — we must hold the person of man sacred. If we would not divest ourselves of humanity, we must cherish our own flesh…. How much care and exertion is due to the safety of the soul, which is of immeasurably higher value in the sight of God?!”
Calvin comments: “We should not unjustly do violence to anyone…. Aid, as far as we can, the miserable who are unjustly oppressed!…. With Him…, anger is accounted murder!” So too suicide, abortion, genocide, and euthanasia. For not just the first six Commandments would prolong human life. Indirectly, also the last four. For ‘You shall not kill’ — means look after yourself, too!