By Act IV, the wages of political strife and battle seem to have taken their toll upon both Brutus and Cassius. In Act IV, Scene 2, Lucilius, a friend to Brutus, informs Brutus that he was has not been well received by Cassius; Brutus understands the implications of this news:
Thou hast described
A hot friend cooling. Ever note, Lucilius,
When love begins to sicken and decay
It useth an enforced ceremony. (4.2.20-23)
When Cassius arrives, he tells Brutus he has wronged him, but Brutus takes him aside and warns him to show no dissension before the troops. They, then, enter Brutus's tent where Cassius expresses his displeasure with Brutus's having punished Lucius Pella for taking bribes. Ironically, Cassius, who in Act I did not worry about being honorable but wanted Brutus as a conspirator because he is honorable is now angry with Brutus for his integrity. On the other hand, Brutus is disturbed by Cassius's pragmatism in accepting money for the army, but it was this very practical approach to problems that led Brutus to decide to join Cassius and the others in the plot to assassinate Caesar. For example, when Cassius urges Brutus to let the "enemy seek us" by not going to Phillipi but having the troops of the triumvirate march to them, thereby wearying the soldiers and waste their means while their troops will be refreshed and ready, Brutus disagrees, contending that their legions are "brimful, our cause is ripe":
There is a tide in the affairs of men
Which taken at the flood leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
On such a full sea are we now afloat,
And we must take the current when it serves,
Or lose our ventures.(4.3.244-250)
Later in the scene, Brutus sees Caesar's ghost and is told that he will again meet Caesar at Phillipi, Brutus ignores the signs. But, in Act V, Cassius, who earlier has told Brutus that the fault is each person is "not in the stars, but in themselves," changes his stand on omens and gives them credence. Clearly, Brutus and Cassius are at odds with one another as they consider their destinies.