Acts 1:22

to be a witness with us of his resurrection The Resurrection was the central truth, but to bear testimony that it was truly Jesus who had risen, the witness must have known Him well before His crucifixion.

It is quite in accordance with the character of St Luke's narrative that although he is careful to relate how the number of the Apostles was made complete, and the Church thus furnished with that same number of leaders which Jesus had chosen from the first, yet when Matthias has been chosen, he tells us no word about his special actions. These were no doubt of the same character as those of the eleven, but the writer's purpose is only to give typical instances of the Apostolic labours, and to shew how the Gospel was spread abroad exactly as Christ had foretold.