89 There are others who deny any impetratory power to our prayers, or who endeavor to insinuate into men's minds the idea that prayers offered to God in private should be considered of little worth, whereas public prayers which are made in the Name of the Church are those which really matter, since they proceed from the Mystical Body of Christ. This opinion is false; for the divine Redeemer is most closely united not only with His Church, which is His Beloved Spouse, but also with each and every one of the faithful, and He ardently desires to speak with them heart to heart, especially after Holy Communion. It is true that public prayer, inasmuch as it is offered by Mother Church, excels any other kind of prayer by reason of her dignity as Spouse of Christ; but no prayer, even the most private, is lacking in dignity or power, and all prayer is of the greatest help to the Mystical Body in which, through the Communion of Saints, no good can be done, no virtue practiced by the individual members, which does not redound also to the salvation of all. Neither is a man forbidden to ask for himself particular favors even for this life merely because he is a member of this Body, provided he is always resigned to the divine will; for the members retain their own personality and remain subject to their own individual needs. Moreover, how highly all should esteem mental prayer is proved not only be ecclesiastical documents, but also by the custom and practice of the saints.
Source: Mystici Corporis Christi (Vatican.va)