I assume you are talking about The Fall of Man (or the story of Adam) found in Genesis, and the parable of the prodigal son found in the Gospel of Luke.

Similarities:

• Both Adam and the prodigal son were given gifts they did not deserve: Adam, the entire garden of Eden and everything in it; the son, his inheritance which was taken early.
• Both Adam and the prodigal son were irresponsible with their gifts: Adam broke the one rule of the garden (never to eat from the Tree of the Knowledge of Good and Evil); the prodigal son squandered away his money.
• Both Adam and the prodigal son were forgiven by their fathers.

Differences:

• The prodigal son returned to his father for forgiveness.  Adam hid from God and when God found him, Adam was punished.
• Because he asked for it, the prodigal son's forgiveness was immediate.  As soon as he returned to his father he was welcomed with open arms.
• Adam's forgiveness would not come for many years.  The story of Adam is meant to represent the separation of humans from God that was only mended when a Messaiah (Jesus Christ) came and died on the cross.  Christians believe that this was the atonement for Adam's original sin, and therefore all sin of all humans.  Just like the prodigal son was reunited with his father after asking for forgiveness, according to the New Testament, all humans will be reunited with God after asking for forgiveness and accepting that Jesus Christ is the one who made that forgiveness possible.