The (most) unkindest cut of all
Brutus was Caesar's close and trusted friend. To be stabbed by him was even more hurtful than by those who he was less intimate.
English teachers would probably put a red line through any schoolchild's text that included the 'most unkindest'. That Del Boy sounding phrase would be corrected to 'most unkind' or just 'unkindest'. Shakespeare rose far above the concerns of spelling and grammar. As was the manner at the time, he wasn't even interested enough in spelling to be consistent in the spelling of his own name.
[Note: 'I am a weakish speller' is an anagram of 'William Shakespeare'.]
The line is from Shakespeare's Julius Caesar, 1601:
If you have tears, prepare to shed them now.
You all do know this mantle: I remember
The first time ever Caesar put it on;
'Twas on a summer's evening, in his tent,
That day he overcame the Nervii:
Look, in this place ran Cassius' dagger through:
See what a rent the envious Casca made:
Through this the well-beloved Brutus stabb'd;
And as he pluck'd his cursed steel away,
Mark how the blood of Caesar follow'd it,
As rushing out of doors, to be resolved
If Brutus so unkindly knock'd, or no;
For Brutus, as you know, was Caesar's angel:
Judge, O you gods, how dearly Caesar loved him!
This was the most unkindest cut of all;
For when the noble Caesar saw him stab,
Ingratitude, more strong than traitors' arms,
Quite vanquish'd him: then burst his mighty heart;
And, in his mantle muffling up his face,
Even at the base of Pompey's statua,
Which all the while ran blood, great Caesar fell.
O, what a fall was there, my countrymen!
Then I, and you, and all of us fell down,
Whilst bloody treason flourish'd over us.
O, now you weep; and, I perceive, you feel
The dint of pity: these are gracious drops.
Kind souls, what, weep you when you but behold
Our Caesar's vesture wounded? Look you here,
Here is himself, marr'd, as you see, with traitors.
See other phrases and sayings from Shakespeare.