Antony indicates his intention to cause a mutiny when he speaks at Caesar's funeral. The most suggestive lines are these:
Over thy wounds now do I prophesy
Which like dumb mouths do ope their ruby lips
To beg the voice and utterance of my tongue...
Shakespeare must have felt that he needed to foreshadow Antony's double-cross of Brutus and also to demonstrate that Antony was potentially capable of such eloquence. If Antony suddenly made an eloquent speech at Caesar's ability funeral without Shakespeare's audience having any suspicion that he had that talent in him, it would seem out of character. The audience would be likely to attribute Antony's eloquence to Shakespeare himself. But we know from the wonderful soliloquy at the end of Act 3, Scene 1 that Antony is not, as he claims to be in his funeral speech, "a plain blunt man." Perhaps he prefers to pose as a plain blunt man, an rough, uneducated soldier, because this makes him popular with his soldiers and with commoners in general. Also, Antony has lived in Caesar's shadow up to this point and is only now beginning to feel his independent spirit.
There are some beautiful lines in the speech that serves as a prelude to Antony's funeral address. For example:
And Caesar's spirit ranging for revenge,
With Ate by his side come hot from hell,
Shall in these confines with a monarch's voice
Cry “Havoc!” and let slip the dogs of war,
That this foul deed shall smell above the earth
With carrion men, groaning for burial.
"Carrion men" is a striking term. "Carrion" usually refers to dead animals lying in the open, eventually to be eaten by scavengers. In Antony's image the carrion consists of dead and wounded men covering a battlefield and destined to be eaten by birds and animals because there is no one to bury them. That speech foreshadows events that will take place in Italy in the aftermath of Caesar's assassination. There was fighting and rioting all over Italy for years before the events depicted in Shakespeare's play. It was years before before Brutus and Cassius were finally defeated by Antony and Octavius at the battle of Philippi. Shakespeare must have felt that he needed to give some notice of these historical facts. He does so in an unusual way. He has Antony telling about what actually happened in history as if Antony is predicting what is going to happen in the future.
Although Antony calls himself "a plain blunt man," he shows dazzling eloquence in both the soliloquy in Act 3, Scene 1 and the funeral oration in Act 3, Scene 2. Here is an example from the funeral oration:
I tell you that which you yourselves do know;
Show you sweet Caesar's wounds, poor poor dumb mouths,
And bid them speak for me. But were I Brutus,
And Brutus Antony, there were an Antony
Would ruffle up your spirits and put a tongue
In every wound of Caesar that should move
The stones of Rome to rise and mutiny.
These lines are all in the subjunctive mood. They are all unreal and impossible, fanciful. They show Antony's brilliant and poetic mind. He bids Caesar's wounds to speak to the mob. According to Plutarch, it was the sight of Caesar's hacked body that turned the mob against the conspirators. Then Antony figuratively becomes Brutus while Brutus somehow becomes Antony. And finally he asks the stones of Rome to grow arms and legs in order to stand up and participate in the mutiny which it has been his intention to arouse since he received Brutus' permission to speak at Caesar's funeral. Altogether it seems as if Caesar, Antony, Brutus, and the stones of Rome are all beseeching the plebeians to riot. This is remarkable, and it might be said that it was foreshadowed in his earlier speech addressed to Caesar's mutilated body.