Double, double, toil and trouble; Fire burn, and cauldron bubble! - William Shakespeare

Blood will have blood.

To bait fish withal: if it will feed nothing else, it will feed my revenge. He hath disgraced me, and hindered me half a million; laughed at my losses,
mocked at my gains, scorned my nation, thwarted my bargains, cooled my friends, heated mine enemies; and what's his reason?
I am a Jew.
Hath not a Jew eyes? hath not a Jew hands, organs,dimensions, senses, affections, passions?
Fed with the same food, hurt with the same weapons, subject to the same diseases, healed by the same means,
warmed and cooled by the same winter and summer, as a Christian is?
If you prick us, do we not bleed?
If you tickle us, do we not laugh?
If you poison us, do we not die?
And if you wrong us, shall we not
revenge?
If we are like you in the rest, we will
resemble you in that.
If a Jew wrong a Christian, what is his humility? Revenge.
If a Christian wrong a Jew, what should his sufferance be by Christian example?
Why, revenge.
The villany you teach me, I will execute, and it shall go hard but I
will better the instruction.

Conscience is but a word that cowards use,
Devis'd at first to keep the strong in awe:
Our strong arms be our conscience, swords our law.
March on, join bravely, let us to't pell-mell;
If not to heaven, then hand in hand to hell.