The two friends stay with the couple for three days. Quixote tells Basilio that his trick was not dishonorable, because it was meant to achieve a “virtuous end” – a marriage based on love. He advises Basilio to value his wife’s virtue and loyalty above all else.
In the past, Quixote has valued right action over consequence. Basilio inverts this system: he acts deceitfully so that he can marry the person he loves. A wiser Quixote recognizes the value of this unfamiliar system.
Quixote finds a guide to show them the way to the famous Cave of Montesinos, and they set off. They buy several hundred yards of rope on the way and reach the cave the following day, all covered over with weeds and brambles. Quixote clears an opening with his sword and the two other men lower him into the dark opening. They let down all two hundred yards, and after waiting for a half an hour they pull him back up, though they only begin to feel Quixote’s weight a little while later. As they pull him out, he seems to be asleep. When they finally wake him up, he tells them he has seen magnificent, magical sights.
We have seen before that Sancho urges Quixote to sleep through the night and take action in daylight, when the external world is clear and the dream world recedes. Here, Quixote plunges from day into night, from safe reality into a mysterious cavern. Perhaps he has become a little tired of seeking adventure in ordinary, daytime reality, so he is trying to withdraw further into dream life.