They prayed

“So they proposed two, Joseph called Barsabbas, who was also known as Justus, and Matthias. Then they prayed, ‘You, Lord, who know the hearts of all, show which one of these two you have chosen to take the place in this apostolic ministry from which Judas turned away to go to his own place.’ Then they gave lots to them, and the lot fell upon Matthias, and he was counted with the Eleven Apostles.”

Because the Apostles lost Judas, it was “necessary that one of the men who accompanied us the whole time … become with us a witness to his resurrection,” so they prayed for God’s will—“show which one of these two you have chosen” and—“gave lots to them.” Prayer and the ordination procedure, grace and a good strategy—go together. Oratio and actio, prayer and action, are not in opposition but complement each other.

“I chose you from the world, to go and bear fruit that will last, says the Lord.” (Gospel Acclamation)