In those days, Peter, stood up in the midst of the disciples and said… As the fiery spirit to whom the flock was entrusted by Christ and as the leader in the band of the apostles, Peter always took the initiative in speaking: My brothers, we must choose from among our number. He left the decision to the whole body, at once augmenting the honor of those elected and avoiding any suspicion of partiality. For such great occasions can easily lead to trouble.
Did not Peter then have the right to make the choice himself ? Certainly he had the right, but he did not want to give the appearance of showing special favor to anyone. Besides he was not yet endowed with the Spirit. And they nominated two, we read, Joseph, who was called Barsabbas and surnamed Justus, and Matthias. He himself did not nominate them; all present did. But it was he who brought the issue forward, pointing out that it was not his own idea but had been suggested to him by a scriptural prophecy. So he was speaking not as a teacher but as an interpreter.