Jacques comes across Harpagon and Cléante fighting and asks why they're at each other's throats.
Harpagon, who is seeing red at this point, orders Jacques to decide who is in the right. You know, because Harpagon just knows that Jacques will side with him.
Master Jacques gets the men to stand apart and visits each one separately to learn his side of the story.
Jacques lies to each of them about what the other is saying. To Cléante, he says that Harpagon is wiling to give him Mariane as long as he shows respect to his father. To Harpagon, he says that Cléante is willing to completely obey him in all things. Clever Jacques.
Harpagon reaches into his pocket to reward Jacques for his service, but then stops and tells Jacques he'll tip him another time.