Thomas a Kempis (1379-1471)
O Almighty God, let your grace assist us, that we who have undertaken the office of Priesthood, may be able to wait upon you worthily and devoutly, in all purity, and with a good conscience. And if we cannot live in so great innocence of life as we ought to do, grant to us, at the least, worthily to lament the sins that we have committed; and in the spirit of humility, and with the full purpose of a good will, to serve you more earnestly for the time to come. Through Christ our Lord. Amen.