In the story we know that Faustus, because of dissatisfaction of what knowledge he has, tried the world of magic and sold his soul to the Devil in exchange of great power for twenty four years. When he reaches the 24th year, a realization hits him that he don't want to die in be in hell with the devil because he knows what awaits him there. Fear becomes real at his last hour and he tried to believe that there is God who might forgive him and help him but still hesitated to do so.
If we believe in God, we believe that no matter what our sins are, He is more than willing to forgive us. In case of Faustus, if he had seek God's forgiveness at the last meet, if he had repented on the sins he had chosen to live for the past 20 years, he will be restored spiritually. At the last minute of dying, at least he would be grateful because he wont be going to hell with the Devil.