Given the circumstances, the advice that Cassius gives to Brutus at the beginning of Act IV, Scene 3 of Julius Caesar is probably the most practical course of action for them both in the circumstances. Cassius and Brutus are commanding armies in the middle of a military campaign that is a matter of life and death to them both. They clearly have a difference of opinion on how strictly ethical standards should be adhered to in times of crisis. Cassius would go easy on Lucius Pella for bribery, while Brutus would be strict.This is a matter of detail and would be best left for later, instead of being built up into a major disagreement.
Brutus, for all his high standards, has a streak of moral pettiness in him that emerges under pressure and shows fully in this scene. For instance, he only accuses Cassius of taking bribes after Cassius defends Lucius Pella. If this were an important fault in Cassius, why did Brutus keep it back and only throw it in his face as a weapon in a quarrel? As the scene develops, Cassius repeatedly tries to pull back from the brink, only to have Brutus go out of his way to provoke him:
You have done that you should be sorry for.
There is no terror, Cassius, in your threats,
For I am arm'd so strong in honesty,
That they pass by me as the idle wind
Which I respect not.
It turns out in the end that Brutus is being so sensitive because he is not such a good philosopher as he pretends to be, and he has been affected by the news of his wife's death.