Judas, the son of Iscariot, was the only southerner amongst Jesus' disciples. To have made it to one of the twelve, we can deduce that he had innate attributes that qualified him for the Master's pick. Like the other eleven, his brief was first to be with Jesus and then to make disciples of men. They were together with the master day and night, save when they were sent to the city on a mission trip. 

True, there was Peter, James and John, men we can call the first three, but there was Judas, the treasurer. Considering that money was an essential part of their ministry, being trusted to take charge of the purse reveals volumes. We were not told that Judas had any prior experience (Mathew was a tax collector) with keeping funds, but neither did the others know their new mission. We would be safe if we concluded that with the Master's training, they would get the necessary skills. The analogy would be fine if the bible were not careful to note that Judas was a thief who now and again helped himself with the contents of the coffers. Why, then, would the Master put him in charge? We may never know the answer to the question, but we can rest in the fact that God's ways are higher than man's.

How can a man spend three years hearing the many messages on life and heart matters and be unregenerated? So Judas was not only calculating, but he was also evil.