On the Catholic Priesthood
Praying for Priests
" Hour by hour", Father Gerald said, "Somewhere the Mass is always being offered. And wherever the Mass is being offered, because of the One who is offering it, God through the Mass is attaining at every moment a greater glory than all the rest of us adopted children could take away from Him." This offers a second powerful motive why the faithful should pray for priests, to insure that God be continuously, and in the highest degree, glorified by the re-enactment of Calvary.
How will the prayer contribute to this divine praise? By warding off the evil spirit who sees in the Mass the greatest hindrance to his demonic activity. " Therefore, it is the Mass that counts, and that is why the arch-enemy of God tried to destroy it as far as he could at the time of the Reformation, and still tries to eliminate the Mass and the priesthood, the priesthood and the Mass."
The devil knows that every Mass gives immeasurable glory to the Divine Majesty, which he hates. So he does everything in his power to seduce priests into his camp so they will not offer Mass, or offer it less often, or less devoutly; anything to prevent God being given the glory and souls from receiving the graces that flow from the Holy Sacrifice of the Mass.
That is why believing Catholics are not surprised to be told, "you must always in your secret espousal of God's cause, in working for God's cause, always carry a special place in your prayers and in you heart for the sanctification of the priesthood and the sacredness of the Mass." The two go together. Every prayer for the sanctification of priests, to protect them from the malice of the devil, is a prayer for the greater glory of God through the Mass which priests alone can offer to the Heavenly Father.
A moment's reflection should tell a believer that "the priesthood is a terrifying exaltation. " That is why, "you can do nothing more consoling to His Sacred Heart than to pray for His priesthood; for by the institution of the priesthood God has committed His stainless honor, His deepest interests, to the keeping of created clay." Among the saints, "St. Teresa of Jesus knew this and that is why she made prayers for the priesthood the first duty of her Carmelite family. A faithful priest is God's greatest consolation, and unfaithful priest the source of His deepest sorrow." Then speaking for himself, Father Gerald asked, "I would beg one decade of the Rosary each day, thanking Mary for my vocation and asking that I may be each day nearer and dearer to her Heart and to her Son Divine."
Source: A Prophet for the Priesthood, A Spiritual Biography of Father Gerald M.C. Fitzegerald. by Fr. John A. Hardon, S.J.