Brutus becomes disillusioned with his partner Cassius just before the Battle of Philippi, and during their violent quarrel Brutus tells him what he thinks of his behavior and his character. Most strikingly, Brutus says:
Let me tell you, Cassius, you yourself
Are much condemned to have an itching palm,
To sell and mart your offices for gold
To undeservers. (IV.2)
It is significant that right after Caesar's assassination when Brutus and Cassius are trying to win Antony's acceptance of their new order, Cassius tells Antony:
Your voice shall be as strong as any man's
In the disposing of new dignities. (III.1)
Since this power is of great importance to Cassius, he naturally assumes it would carry equal weight with Antony. There is nothing Cassius cares as much about as gold. He is a real miser. Caesar says he "has a lean and hungry look." This is because he hates to spend money even on himself. It would seem that Cassius is ambitious for political power mainly because of what he could gain from it in property and gold. He would have been a corrupt ruler if he had managed to stay in Rome or if he and Brutus had won the crucial battle at Philippi.
Casca understands Cassius very well. They grew up together and went to school together. When Cassius invites Casca to dinner, Casca bluntly responds:
Ay, if I be alive, and your mind hold, and your dinner worth the eating. (I.2)
He has dined at Cassius' home before and knows what kind of meal to expect. It is amusing that after their quarrel, when Brutus calls for a bowl of wine and says, "In this I bury all unkindness, Cassius," Cassius says:
My heart is thirsty for that noble pledge.
Fill, Lucius, till the wine o'erswell the cup.
I cannot drink too much of Brutus' love.
Cassius is a greedy miser. Both qualities are shown in these lines. He cannot drink too much of Brutus' love--or of Brutus' wine. He is an opportunist. Cassius himself seems to acknowledge this early in the play when he says:
Well, Brutus, thou art noble; yet I see
Thy honorable mettle may be wrought
From that it is disposed. Therefore it is meet
That noble minds keep ever with their likes;
For who so firm that cannot be seduced?
Caesar doth bear me hard, but he loves Brutus.
If I were Brutus now, and he were Cassius,
He should not humor me. (I.2)
What this says about Cassius is appalling. He is exclusively concerned about his own welfare. He wants to achieved the absolute power he was seeking. With Caesar gone, Cassius can profit personally, although the Roman people might be no better off than ever.