The clients of this most merciful Mother are very fortunate. She helps them both in this life and in the next, consoling them and sponsoring their cause in Purgatory. For the simple reason that the Souls in Purgatory need help so desperately, since they cannot help themselves, our Mother of Mercy does so much more to relieve them. She exercises over these Poor Souls, who are the spouses of Christ, particular dominion, with power to relieve them and even deliver them from their pains. See how important it is then to have devotion to this good Lady, because she never forgets her servants as long as they suffer in these flames. If she helps all the Poor Souls, she is especially indulgent and consoling to her own clients.” 

 -Saint Alphonsus Liguori, Doctor of the Church, The Glories of Mary