what was the significance of Antony's final speech

Antony said that of all the conspirators only Brutus believed that he was killing Caesar to uphold the Roman Republic; the others were simply jealous and power hungry. Antony continues, saying, "his life was gentle, and the elements / So mixed in him that nature might stand up / And say to all the world 'This was a man'" (5.5.74).

Brutus' inability to overcome his internal struggle allows Antony to say, "This was the noblest Roman of them all" (5.5.67). He is implying that only Brutus really believed that he was killing Caesar to uphold the Roman Republic. However, the audienve must remember how easily Cassius manipulated Brutus into murdering Caesar. Despite his seeming eagerness to achieve power, Brutus is the only conspirator to maintain his humanity and dignity throughout the play. He stands as a symbol of honor against the dishonorable Cassius who lies, manipulates, and wishes to take bribes, and Brutus' rhetoric implies that he would never have killed Caesar except to defend the Roman Republic. Thus Antony continues his epilogue for Brutus, saying, "his life was gentle, and the elements / So mixed in him that nature might stand up / And say to all the world 'This was a man'" (5.5.74)

Source(s): http://www.gradesaver.com/julius-caesar/study-guide/section5/