Catechism of The Catholic Church #1578

1578 No one has a right to receive the sacrament of Holy Orders. Indeed no one claims this office for himself; he is called to it by God. Anyone who thinks he recognizes the signs of God’s call to the ordained ministry must humbly submit his desire to the authority of the Church, who has the responsibility and right to call someone to receive orders. Like every grace this sacrament can be received only as an unmerited gift.