The Crucified Ones in History is a book full of stories about revenge-seekers who inflicted harsh punishments on their enemies. What one realizes as one reads this book (which is probably what the author wants us to realize) is that killing their enemies was not enough to quench their thirst for revenge. The irony that the author conveys is that the crucified person, for instance, ceases to feel pain after his soul departs from his body. Meanwhile, the revenge-seeking killer will never find peace or happiness because the fire of revenge has engrossed, or rather taken over, his entire being.
The book relates the lives of some of the leaders of Banu ‘Abbaas; they missed the opportunity of killing their rivals from Banu ‘Umayya simply because the latter group died before the former group took hold of office. Still enraged, one of them would remove the corpse of his enemy from the grave and whip it or crucify it and then burn it. So understand this: the seeker of revenge will always feel more pain and misery than the object of his revenge because he has lost both peace and serenity.
"Enemies do not afflict the ignorant person near as much as the ignorant person afflicts himself."
(And when they meet you, they say, ‘We believe.’But when they are alone, they bite the tips of their fingers at you in rage. Say: ‘Perish in your rages it (Qur’an 3: 119)