After our Blessed Lord's Ascension His disciples came together, with Mary His mother and the eleven Apostles, in an upper room at Jerusalem. The little company numbered no more than one hundred and twenty souls. They were waiting for the promised coming of the Holy Ghost, and they persevered in prayer. Meanwhile there was a solemn act to be performed on the part of the Church, which could not be postponed. The place of the fallen Judas had to be filled, that the number of the Apostles might be complete. Saint Peter, therefore, as Vicar of Christ, arose to announce the divine decree. What the Holy Ghost had spoken by the mouth of David concerning Judas, he said, must be fulfilled. Of him it had been written, His bishopric let another take. A choice, therefore, was needed of one among those who had been their companions from the beginning, who could bear witness to the Resurrection of Jesus.
Two were named of equal merit, Joseph called Barsabas, and Matthias. After praying to God, who knows the hearts of all men, to show which of these He had chosen, they cast lots, and the lot fell upon Matthias, who was thereby numbered with the Apostles. It is recorded of the Saint, wonderfully elected to so high a vocation, that he was remarkable for his mortification of the flesh. It was thus that he made his election sure.
He preached in Judea where he was persecuted by both Jews and Gentiles, and died by stoning, a victim of their pursuits, in the year 63. His body was taken to Rome by Saint Helena, mother of Constantine, some 250 years later. A church there bears his name.
"The inner life of another that is known to God alone becomes to a much less degree open to us through friendship. It partially fills the desire of our incomplete, lonely hearts for completeness in another. Friendship brings out the best in a person through forgetfulness of self." - St. Thomas Aquinas