In act three, what does my credit now stands on such slippery ground qouted by Antony ?

 Antony is in great quandary after the cold-blooded
assassination of Julius Caesar. Those who have killed Julius Caesar can also eliminate
him from the scene, a fact well-known to Antony. However, he wishes to avenge Caesar's
death. Therefore, when he is invited by Marcus Brutus for a discussion, he is cautious
and on his guard.

He first wails and laments the death of
Caesar and then asks if he was the next one to bleed to death. He also requests the two
to "fulfill their pleasure" when their hands were reeking with the blood of Caesar. Not
even in thousand years will he get a better time to be killed than by the same daggers,
the same people, the same hour and the same manner as was
Caesar.

Brutus, however, requests Antony to see thair
hearts full of brotherly love and  not their hands full of blood. He further adds that
for Antony, their swords had "leaden points". Cassius also adds that when the new
republic will be formed, Antony's voice will be given same consideration as any man in
deciding the new posts of honour.

Antony senses a chance,
and requests the conspirators to place their hands in his hand as a new found
friendship. It is here that he remarks that his "credit" now stands on such slippery
ground. Credit means reputation.According to Antony, it will be very difficult for him
to explain the reason for his joining hands with the murderers of Julius Caesar and adds
that he will either be called a flatterer or a coward, both will actually ruin and
tarnish his image and reputation. But in reality ,it gives him an outside chance to save
his life and to wait for the most opportune moment to give the conspirators and
murderers of Julius Caesar a taste of their own medicine.