"Recommend unceasingly in you prayers your sons to the Lord with all possible earnestness, especially during holy Mass, and at your holy Communions, Recommend them also to the Blessed Virgin Mary, to their guardian angels, to the Saints whose names were given to them in holy baptism, and to all holy priests. Do so above all when one of them has to leave home to make his preparatory studies for the priesthood at academies and colleges. Ah, what great danger will he not run of there becoming a victim to frivolousness, vices to a dissolute life, and even of becoming unfaithful to his Vocation! Unite, therefore, with the Father in making him firm and strong against such dangers as much as you can; confide him, if possible, to a trustworthy family. But besides all this, never cease to pray with the utmost fervor for him.
-- The Christian Mother, The Education of Her Children and Her Prayer. (Rev. W. Cramer, 1880)
Prayer for a Son who already has a Vocation to the Priesthood
O God! Thou who has deigned to bestow on me, so unworthy of it, the inestimable grace of being mother of a son called to the dignity of the priesthood, I entreat Thee with a thankful heart to preserve in him the good work Thou hast begun, and to bring it to perfection. Ah! How easily may this sublime vocation, through one's own fault, be lost!
How great and numerous are the dangers of becoming unfaithful to it! I entreat Thee, therefore, O God! Defend my son from these dangers; lead him so that he may without wavering persevere in the course beset by so many dangers, and keep constantly before his eyes the sublime end which he has in view. Visit him with the most precious blessing of Thy grace, that he may grow up and advance in true Christian piety. Assist him in his studies, in order that, well provided with science and understanding, he may be able to fulfill the duties of his vocation in a useful and profitable manner.
Give Thy grace and help also to me, that I may discharge the duties of my vocation to my son with the greatest fidelity and zeal, and omit nothing which may serve to give him an education corresponding to his high calling. Bless then, all-merciful God, my endeavor with the power of Thy grace. Amen
Ye holy mothers who have educated holy priests, and who have, therefore, for all eternity a share in all the good they have done, and in their glory and happiness; and ye priests now reigning in heaven, pray for me, and obtain for me the grace so to educate my son that may one day also become a worthy priest. Obtain also for my son the grace of perseverance, that he may triumph over the assaults of Satan, and be admitted among the number of the priests of the Most High. Amen