Final answer:
In Act IV, scene iii of 'Julius Caesar', Brutus argues with Cassius, emphasizing the need for honor and justice in their cause after Caesar's assassination, while also dealing with his personal grief of losing Portia.
Step-by-step explanation:
In Act IV, scene iii of Shakespeare's Julius Caesar, Brutus presents his argument amid a quarrel with Cassius. His primary contention revolves around the ideals of honor and justice as opposed to greed and corruption. Brutus condemns Cassius for accepting bribes, which he believes undermines the integrity of their cause – the assassination of Caesar, which was meant to save the Republic from tyranny. Brutus insists on maintaining moral high ground, believing their actions must reflect the righteousness of the cause they earlier claimed to uphold.
Additionally, the scene also shows Brutus struggling with personal grief following the death of Portia, his wife. Despite his emotional state, he strives to stay focused on the political crisis that they face and urges Cassius to move forward in their military campaigns with honor, as well as preparing for the looming battle against Mark Antony and Octavius, Caesar's supporters.