A couple of days ago was the feast of St. Matthias, the Apostle. Here is the very relavent collect:
O Almighty God, who into the place of the traitor Judas didst choose thy faithful servant Matthias to be of the number of the twelve Apostles: grant that thy Church, being alays preserved from false Apostles, may be ordered and guided by faithful and true pastors. Through Jesus Christ our Lord, who liveth and reigneth with you and the Holy Spirit, one God, world without end. Amen.