The pact with Lucifer
Using Mephistophilis as a messenger, Faustus strikes a deal with Lucifer: he is to be allotted twenty-four years of life on Earth, during which time he will have Mephistophilis as his personal servant. At the end he will give his soul over to Lucifer as payment and spend the rest of time as one damned to Hell. This deal is to be sealed in Faustus's own blood. After cutting his arm, the wound is divinely healed and the Latin words "Homo, fuge!" (Flee, man!) then appear upon it. Despite the dramatic nature of this divine intervention, Faustus disregards the inscription with the assertion that he is already damned by his actions thus far and therefore left with no place to which he could flee. Mephistophilis brings coals to break the wound open again, and thus Faustus is able to take his oath that was written in his own blood.
Wasting his skills
Faustus begins by asking Mephistophilis a series of science-related questions. However, the devil seems to be quite evasive and finishes with a Latin phrase, "Per inoequalem motum respectu totius" ("through unequal motion with respect to the whole thing"). This sentence has not the slightest scientific value, thus giving the impression that Mephistophilis is untrustworthy.
Two angels, one good and one bad, appear to Faustus: the good angel urges him to repent and revoke his oath to Lucifer. This is the largest fault of Faustus throughout the play: he is blind to his own salvation. Though he is told initially by Mephistophilis to "leave these frivolous demands", Faustus remains set on his soul's damnation.
Lucifer brings to Faustus the personification of the seven deadly sins. Faustus fails to see them as warnings and ignores them.
From this point until the end of the play, Faustus does nothing worthwhile, having begun his pact with the attitude that he would be able to do anything. Instead, he merely uses his temporary powers for practical jokes. Realising that he gave up his soul for no good reason, Faustus appears to scholars and warns them that he is damned and will not be long on the earth. He gives a speech about how he is damned and eventually seems to repent for his deeds. Mephistophilis comes to collect his soul, and we are told that he exits back to hell with him.
At the end of the play, devils carry Faustus off the stage. In the later 'B text' of the play, there is a subsequent scene [V.iii] where the three scholars discover his remains strewn about the stage: they state that Faustus was damned, one scholar declaring that the devils have torn him asunder.