an eye for an eye
The principle of justice that requires punishment equal in kind to the offense (not greater than the offense, as was frequently given in ancient times). Thus, if someone puts out another's eye, one of the offender's eyes should be put out. The principle is stated in the Book of Exodus as “Thou shalt give life for life, eye for eye, tooth for tooth, hand for hand, foot for foot.”
Sorry, the Pope is not a Jew.
"Ye have heard that it hath been said, An eye for an eye, and a tooth for a tooth: But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also. And if any man will sue thee at the law, and take away thy coat, let him have thy cloke also. And whosoever shall compel thee to go a mile, go with him twain. Give to him that asketh thee, and from him that would borrow of thee turn not thou away."
None of this is to say that one cannot defend one's self, but retribution, preemptive or otherwise is not a Christian concept.