"Had you rather Caesar were living and die all slaves, than that Caesar were dead, to live all free men?"
"As Caesar loved me, I weep for him; as he was fortunate, I rejoice at it; as he was valiant, I honour him: but, as he was ambitious, I slew him. There is tears for his love; joy for his fortune; honour for his valour; and death for his ambition"
"Hear me for my cause, and be silent, that you may hear: believe me for mine honour, and have respect to mine honour"
In this quote he explains his reasoning why he killed Caesar and tries to persuade the crowd. Explaining that if he wasnt killed then they would become slaves is a good argument to get them on his side.
Brutus explains his closeness and his love for Caesar which gives a heartfelt emotion to his persuasion. even though he loved him he knew that because he knew what was best for Rome and his love for Rome was much greater he had to do it.
His status is much higher than the people who were angry about his approach on removing Caesar from power. he is closest to the government and know much more about politics which makes him a credited source to why the murder was the right thing to do.