I’m preparing for a sermon on Sunday on the story of David sparing Saul’s life even though Saul had been trying to kill him (1 Samuel 24). In the course of my research, I came across a passage from Arcana Coelestia on “the law of retaliation”:
The hells, or the evil who are there, are in the continual cupidity of doing evil to others, for this is the very delight of their life; and therefore as soon as it is permitted, they do evil, caring not to whom, whether he is evil or good, whether he is a companion or an enemy; and as it is from a law of order that evil returns upon those who intend evil, consequently, when it is permitted by the law, they rush on them. This is done by the evil who are in the hells, never by the good who are in the heavens, for these latter are in the continual desire of doing good to others, because this is the delight of their life; and therefore as soon as there is an opportunity, they do good both to foes and to friends; nay, they do not resist evil, for the laws of order defend and protect what is good and true. Hence it is that the Lord says, “Ye have heard that it hath been said, An eye for an eye, and a tooth for a tooth; but I say to you that evil must not be resisted. Ye have heard that it hath been said, Thou shalt love thy neighbor, and hate thine enemy; but I say to you, Love your enemies, bless them that curse you, impart benefits to them that hate you; that ye may be sons of your Father in the heavens” (Matt. 5:38, 39, 43-45).
 It frequently happens in the other life that when evil spirits wish to inflict evil on the good, they are grievously punished, and that the evil which they intend to others returns upon themselves. At the time this appears as if it were revenge from the good; but it is not revenge, neither is it from the good, but from the evil, to whom an opportunity is then given from the law of order. Nay, the good do not wish evil to them, but still they cannot take away the evil of punishment, because they are then kept in the intention of good-just like a judge when he sees a malefactor being punished, or like a father when he sees his son punished by his master. The evil who punish do it from the cupidity of doing evil; but the good from the affection of doing good. From all this it can be seen what is meant by the Lord’s words concerning love for an enemy, in Matthew, as above; and concerning the law of retaliation, which was not abrogated by the Lord, but explained; namely, that they who are in heavenly love ought not to have delight in retaliation or revenge, but in imparting benefits; and that the very law of order, which protects what is good, performs it from itself, through the evil ones. (Arcana Coelestia n. 8223)
I love the way this passage describes an angel’s attitude toward punishment: he sees that it has to happen, but doesn’t enjoy it. But (and maybe this is a sign that I’m angelic!) I don’t like the fact that evil spirits punish each other. We often talk about “evil punishing itself” – but the reality is, the way that happens in the other world is that when a person does evil, he removes himself from the Lord’s protection, and other evil spirits get to attack him. Hell is hell.