Mark Antony shows considerable patience and self-control in appearing to make his peace with the conspirators. As a loyal friend of Caesar, he hates what the assassins have just done; he believes that they are traitors and must pay for their crimes. But he's not going to make a move just yet; it's way too dangerous. Having just murdered Caesar, the conspirators wouldn't think twice about meting out a similar fate to Antony if he dared to utter a word of protest.
Mark Antony understands that if he's going to gain revenge for his murdered friend he'll have to bide his time. So he plays along, instructing his servant to send Brutus the message that Antony regards him as "noble, wise, valiant, and honest." He further agrees to follow Brutus as leader from now on. Brutus is overjoyed at what appears to be Mark Antony's acquiescence. Cassius, however, is not so sure; he knows just how close Antony was to Caesar. But for now it seems that Antony's reconciled to the conspirators and the foul deed they have committed. But in actual fact, he's just biding his time, waiting for the right moment to strike back against what he regards as a murderous gang of traitors.