Question

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 enforced 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 how does lucillius, a minor character in the play, help advance the plot in this passage? lucillius is protective of cassius so he diminishes the seriousness of the conflict. lucillius tells brutus that cassius intends to attack brutus, increasing the tension and conflict. lucillius does not tell brutus much about cassius, which causes brutus to question the loyalty of lucillius. lucillius explains that cassius is far less friendly than he once was, and brutus uses the information to confirm his judgement that cassius is turning against him.

Explanation:

Lucillius describes Cassius' changed behavior towards Brutus. This information helps Brutus suspect Cassius is turning against him, advancing the plot.

Answer:

Lucillius explains that Cassius is far less friendly than he once was, and Brutus uses the information to confirm his judgement that Cassius is turning against him.