Acts 1:2
1:2 until the day he was taken up to heaven, after he had given orders by the Holy Spirit to the apostles he had chosen.
Acts 1:25-26
1:25 to assume the task of this service and apostleship from which Judas turned aside to go to his own place.”
1:26 Then they cast lots for them, and the one chosen was Matthias; so he was counted with the eleven apostles.