To begin with, both of these men had very promising futures. Judas and Peter were chosen to receive a very valuable education, the personal teachings of Christ. They were handpicked by Jesus himself to be a part of the twelve apostles and were given the opportunity to learn right from wrong. Among other things, they were taught to pray, they had Jesus wash their feet, and they had the privilege of attending the last supper. In spite of all that Christ had given and taught them, He knew and warned Peter and Judas that they would both betray Him. Even though they had been warned, Judas and Peter went on to betray Jesus anyways. This made them grave sinners. After their betrayals, they realized how gravely they had sinned and they both felt remorse over their actions and repented. Though they had many similarities, it was their differences that determined their eternal fates.
Even though Peter and Judas both betrayed Christ, they did so very differently. Judas revealed Jesus' identity to the Roman soldiers for a cash prize. This act of betrayal allowed the Romans to crucify Jesus. When Jesus was taken and tried for supposed crimes against the Roman empire, Peter betrayed Christ by denying that he ever knew the man. This act of betrayal was one of cowardice and allowed Peter to be spared of crucifixion. Although they both felt great remorse for their sins, they dealt with the guilt differently. Judas continued to despair over his actions, and instead of making amends to become worthy of forgiveness, he took his own life.