The comedy of Scene 3 relies upon a subtle reversal. Earlier, Orgon had refused to believe anything evil about Tartuffe. Now the entire position is reversed and he cannot convince his own mother of Tartuffe's hypocrisy. The utter exasperation which he feels delights the audience because he had earlier so exasperated everyone else by his stubbornness. Note also that the clichés that Madame Pernelle recites about Tartuffe and all righteous men in general are almost exactly the same clichés that Orgon used earlier. The entire episode is summed up for us when Dorine says, "You wouldn't trust us earlier; now it's your turn not to be trusted."
M. Loyal, both by his name and his deportment, is highly comic. He arrives thinking naively that he brings good news because any subject is anxious to obey the law, even if the law is dispossessing him of his house. He is also proud to have been a loyal servant to Orgon's father and he is continuing his loyalty by evicting Orgon. It is indeed comic that every time Orgon starts to object, M. Loyal reminds him that a man so esteemed as Orgon would never think of trying to obstruct justice and a man so upright as Orgon must be pleased to help the law function without difficulty.
Again, Dorine makes Orgon the butt of her sarcasm when she explains that Tartuffe is doing him a favor because only yesterday Orgon said that material things enslave the soul and for salvation one should look to Heaven and not the possessions of this world. She stands as a constant reminder to Orgon of his own stupidity and gullibility.
