Answer Not Evil with Evil

Continuing in my reading of Thomas Boston's commentary on the Sixth Commandment, I found the following. He makes the point that obedience to the commandment requires that we sometimes act in self-defense. Yet he points out that God certainly does not approve of the idea that the violent should be overcome with violence of our own, except as a last resort. And even in that case, the measure of force should not exceed that which is necessary to repel or subdue the attacker.

"[Christians should use] just self-defence against violence offered unto us by others unjustly, Luke 22.36. So a man ought to defend himself if he can, against thieves or robbers; and therefore it is said, 'If a thief be found breaking up, and be smitten that he die, there shall no blood be shed for him,' Exod. 22.2. Yet this must be only in the case of necessity, where the violence cannot be escaped but by a violent repelling it; for all violent courses must be the last remedy, Luke 6.29. Where a soft reception will still the violence offered, it is not the spirit of Christ, but of Satan, that repels violence with violence. And when it is necessary, no greater violence may be offered than what is necessary to repel the attack, Exod. 2.2,31."