Primary Source
From John Adams's Summation at the Boston Massacre Trial
I will enlarge no more on the evidence, but submit it to you. Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passions, they cannot alter the state of facts and evidence: nor is the law less stable than the fact; if an assault was made to endanger their lives, the law is clear, they had a right to kill in their own defence; if it was not so severe as to endanger their lives, yet if they were assaulted at all, struck and abused by blows of any sort, by snow-balls, oyster-shells, cinders, clubs, or sticks of any kind; this was a provocation, for which the law reduces the offence of killing, down to manslaughter, in consideration of those passions in our nature, which cannot be eradicated. To your candour and justice I submit the prisoners and their cause.
The law, in all vicissitudes of government, fluctuations of the passions, or flights of enthusiasm, will preserve a steady undeviating course; it will not bend to the uncertain wishes, imaginations, and wanton tempers of men. To use the words of a great and worthy man, a patriot, and an hero, and enlightened friend of mankind, and a martyr to liberty … "The law, (says he,) no passion can disturb. 'Tis void of desire and fear, lust and anger. … It does not enjoin that which pleases a weak, frail man, but without any regard to persons, commands that which is good, and punishes evil in all, whether rich, or poor, high or low, 'Tis deaf, inexorable, inflexible. On the one hand it is inexorable to the cries and lamentations of the prisoners; on the other it is deaf, deaf as an adder to the clamours of the populace.
Quoted in the Legal Papers of John Adams