Evening finds Faust in his study. The poodle is still with him. Faust's soul is tranquil after his happy afternoon, and he feels confident of finding peace. He says:
Ah, when in our narrow cell
The lamp once more imparts good cheer,
Then in our bosom — in the heart
That knows itself — then things grow clear.
Reason once more begins to speak
And the blooms of hope once more to spread;
One hankers for the brooks of life,
Ah, and for life's fountain head.
But Faust's depression begins to return with these last words. To renew his inspiration he sets about translating into German the Gospel of Saint John, but cannot get past the first line, "In the beginning was the Word." After making several attempts to select a rendition that satisfies him, Faust finally decides on, "In the beginning was the Deed."
This episode crystallizes one of the main philosophical themes of the poem — Goethe's conception that action is the creative and ruling force of the universe. This is the metaphysical meaning of Faust's final translation.
The poodle begins to growl and continues to do so as long as Faust goes on reading the Bible. Faust realizes that some mysterious spiritual presence has taken on the form of the dog. He uses a magical incantation to force it to appear. In an instant Mephistopheles stands before him in the guise of a travelling scholar.
This is a crucial moment. Mephisto has been in pursuit of his intended victim ever since making the wager with God, but it was up to Faust to take the first step in his own seduction by recognizing and invoking the devil. This act confirms Mephisto's suspicion of Faust's disgust with positive methods of finding satisfaction and illustrates Faust's movement toward the nihilistic cynicism which characterizes the devil. Mephisto's costume is purposely chosen to make Faust feel at ease with him, and to prevent him from becoming frightened as he had been by the terrifying supernatural appearance of the Earth-Spirit.
Faust senses his visitor's identity, but Mephistopheles refuses to reveal his name. Instead he describes himself by explaining his function in the divine plan, saying he is
A part of that Power
Which always wills evil, always procures good . . .. . . the Spirit which always denies.
A metaphysical debate follows concerning Mephisto's description of himself as only a part of a whole — a concept which Faust finds hard to accept. After their talk Faust invites Mephistopheles to visit him again. The devil prepares to leave but cannot go because Faust has not released the spell that invoked him. Faust refuses to free Mephistopheles. The unexpected discovery that even the devil is subject to a form of law makes him wonder about the possibility of making a contract with him. He intends to force Mephistopheles to buy his freedom.
The devil is not as powerless as he has been pretending, however. He calls up a choir of spirits who lull Faust to sleep with an idyllic song about the sensual pleasures of pagan, southern lands. Next Mephistopheles summons the aid of some mice and makes his escape. When Faust awakens the room is empty. He wonders whether he has been dreaming.
Faust's belief that Mephisto's appearance was only a dream is one of many hints that the devil is partly a symbolic representation of hidden aspects of Faust's personality (of human nature in general).