More then says because he’s in prison and only has a coal with which to write he can’t respond fully to the view that one ought harm an evil man lest he cause even greater harm to such as are innocent and good.
He counsels us that even if it be our formal office to punish an evil man — for instance, if we’re an agent of the government executing legitimate justice — that even then we ought to
leave the desire of punishing unto God, and unto such folk as are so grounded in charity and cleave so fast to God, that no secret shrewd cruel affection, under the cloak of just and virtuous zeal, can creep in, and undermine them.
Let us who are no better than men of a mean sort [always] pray for such merciful amendment in others as our conscience sheweth us we have need of in ourselves.
For more on this see Bishop Nikolai Velimirovich on loving our enemies.