Read the excerpt from act 4, scene 2, of The Tragedy of Julius Caesar. [BRUTUS.] He is not doubted—A word, Lucillius.
How he received you let me be resolved.

LUCILLIUS. With courtesy and with respect enough,
But not with such familiar instances,
Nor with such free and friendly conference,
As he hath used of old.

BRUTUS. Thou hast described
A hot friend cooling. Ever note, Lucillius:
When love begins to sicken and decay
It useth an enforcèd ceremony.
There are no tricks in plain and simple faith;
But hollow men, like horses hot at hand,
Make gallant show and promise of their mettle;
But when they should endure the bloody spur,
They fall their crests and, like deceitful jades,
Sink in the trial.

Which central idea is reflected in this passage?

It is the fate of Brutus and Cassius to rule Rome together after winning the battle against Antony and Cassius.
The friendship and confidence between Cassius and Brutus is deteriorating.
Brutus says he is sinking under the burden of leadership and needs help from Cassius.
Lucillius explains the need for compromise between Brutus and Antony in order to survive the battle.