Genesis 9:6

6.Whoso sheddeth man’s blood (291) The clause in man which is here added, has the force of amplification. Some expound it, ‘Before witnesses.’ Others refer it to what follows, namely, ‘that by man his blood should be shed.’ (292) But all these interpretations are forced. What I have said must be remembered, that this language rather expresses the atrociousness of the crime; because whosoever kills a man, draws down upon himself the blood and life of his brother. On the whole, they are deceived (in my judgment) who think that a political law, for the punishment of homicides, is here simply intended. Truly I do not deny that the punishment which the laws ordain, and which the judges execute, are founded on this divine sentence; but I say the words are more comprehensive. It is written,

‘Men of blood shall not live out half their days,’
(Psalms 55:23.)

And we see some die in highways, some in stews, and many in wars. Therefore, however magistrates may connive at the crime, God sends executioners from other quarters, who shall render unto sanguinary men their reward. God so threatens and denounces vengeance against the murderer, that he even arms the magistrate with the sword for the avenging of slaughter, in order that the blood of men may not be shed with impunity.

For in the image of God made he man. For the greater confirmation of the above doctrines God declares, that he is not thus solicitous respecting human life rashly, and for no purpose. Men are indeed unworthy of God’s care, if respect be had only to themselves. but since they bear the image of God engraven on them, He deems himself violated in their person. Thus, although they have nothing of their own by which they obtain the favor of God, he looks upon his own gifts in them, and is thereby excited to love and to care for them. This doctrine, however is to be carefully observed that no one can be injurious to his brother without wounding God himself. Were this doctrine deeply fixed in our minds, we should be much more reluctant than we are to inflict injuries. Should any one object, that this divine image has been obliterated, the solution is easy; first, there yet exists some remnant of it, so that man is possessed of no small dignity; and, secondly, the Celestial Creator himself, however corrupted man may be, still keeps in view the end of his original creation; and according to his example, we ought to consider for what end he created men, and what excellence he has bestowed upon them above the rest of living beings.