How did Brutus change from his first conversation with Cassius?

While Brutus was once very reluctant to follow Cassius's rhetoric, Brutus now is dealing out the rhetoric himself. Brutus tells the masses that he loved Caesar more than any of them, but that he killed Caesar because he loved Rome more. He says, "As Caesar loved me, I weep for him. As he was fortunate, I rejoice at it. As he was valiant, I honor him. But as he was ambitious, I slew him" (3.2.23-25). Brutus then asks them if they wish him to die for his actions, to which the crowd replies, "Live, Brutus, live, live!" (3.2.44). Lastly, he begs them listen to Mark Antony and to let him depart alone. Thus, he leaves Mark Antony alone to give his oration.