According to a variety of sources, Calvin supported capital punishment in some instances.
As listed here, between 1562 and 1563, the following executions were carried out in "Calvin's Geneva":
- 2 women for witchcraft
- 3 for homicide
- 3 men for raping children
- 2 for sodomy
- 3 for theft (either for several thefts or large sums)
- 1 goldsmith for counterfeiting (beheading)
In his commentary on Genesis 9, he says:
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,’
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.
And on Acts 25:
11.I appeal unto Caesar. After that he hath professed that he doth not refuse to die if he be found guilty, he freely useth such helps as he could find at the hands of men. Wherefore, if we be at any time brought into like straits, we must not be superstitious, but we may crave help of the laws and politic order. Because it is written, that magistrates are made and appointed by God to the praise of the godly ( Romans 13:3; and 1 Peter 2:13). Neither was Paul afraid to go to law under an unbelieving judge; for he which appealeth commenceth a new action. −
Therefore, let us know that God, who hath appointed judgment-seats, doth also grant liberty to his to use the same lawfully. Therefore, those mistake Paul who think that he doth flatly condemn the Corinthians, ( 1 Corinthians 6:1) because they require help of the magistrate for defense of their right, seeing he reproveth in that place a manifest fault, to wit, because they could suffer no wrong, and because they were too much set upon suing one another, whereby they caused the gospel to be evil spoken of.
He also deals with capital punishment (by inference at least, if not directly) in Chapter 20 of his Institutes.
Based upon all of that, it seems Calvin approved of the death penalty being meted-out for crimes according to the jurisprudence of an appropriate government.