Brutus instructs the conspirators to wash their hands in Caesar’s blood and then cry out liberty through the streets.
Brutus is very concerned with public opinion before and after the stabbing of Caesar. He makes sure that they do not kill anyone else (including Mark Antony), and he makes a point to tell the people not to be frightened (many senators saw the conspirators do this), and “ambition's debt is paid” (Act 3, Scene 1). To the other conspirators, he says:
Stoop, Romans, stoop,
And let us bathe our hands in Caesar's blood …
Then walk we forth, even to the market-place,
And, waving our red weapons o'er our heads,
Let's all cry 'Peace, freedom and liberty!' (Act 3, Scene 1
This may seem like an odd thing for someone to do who is trying to make people not afraid of him. Remember, though, that he saw himself as a liberator. As the leader of the conspirators, he was making sure that they were all equally bloody and equally “liberating” the people.
Of course, things did not work for Brutus quite as he intended. When he gave his speech explaining how he had freed Rome from the tyrant, people listened respectfully and he probably thought everything was fine. When he let Mark Antony speak, he probably still thought everything was fine. However, he did not really think things through. He did not really have a clear plan, and Mark Antony and his supporters did.
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 (Act 3, Scene 2)
With his rousing funeral speech, Mark Antony brings the city to mutiny and drives Brutus and Cassius out. After a bloody civil war, Rome was in the hands of the triumvirate.