What reason does Brutus give the people for why Caesar had to die?

In act 3, scene 2, Brutus addresses the crowd at Julius Caesar's funeral to explain why the senators assassinated Caesar, in an attempt to quell the emotional citizens. Brutus begins by asking the citizens to believe that he had honorable intentions and encourages them to judge him fairly after listening to his explanation. Brutus then tells the crowd,

If then that friend demand why Brutus rose against Caesar, this is my answer: not that I loved Caesar less, but that I loved Rome more (Shakespeare, 3.2.18-20).

Brutus continues by asking the citizens if they would rather be slaves because Caesar were living or enjoy their freedom because Caesar is dead. Brutus then directly tells the crowd that it was Caesar's ambition that motivated Brutus to join the conspirators and assassinate Caesar. Brutus says,

But, as he was ambitious, I slew him. There is tears for his love, joy for his fortune, honor for his valor, and death for his ambition (Shakespeare, 3.2.25-27).

The citizens initially accept Brutus's explanation and praise him for saving them from possible tyranny. However, Brutus makes the significant mistake of allowing Mark Antony to deliver his funeral oration. Antony ends up giving a moving, passionate speech, which stirs the crowd to riot against the senators and leads to the Roman civil war.