We find an incident relating to this subject in the Life of Venerable Mary d Antigna. For a long time she had the pious custom of making the Stations of the Cross each day for the relief of the souls departed; but later, for motives more apparent than solid, she did it but rarely, and finally omitted it altogether. Our Lord, who had great designs in regard to this pious virgin, and who desired to make her a victim of love for the consolation of the poor souls in Purgatory,vouchsafed to give her a lesson which serves as an instruction to us all.
A Religious of the same convent, who had died a short time previously, appeared to her, complaining sorrowfully, " My dear sister," she said, " why do you no longer make the Stations of the Cross for the souls in Purgatory? You were formerly accustomed to relieve us every day by that holy exercise ; why do you deprive us of that assistance ? "
Whilst the soul was still speaking our Lord Himself appeared to His servant, and reproached her with her negligence. " Know, my daughter," He added, " that the Stations of the Cross are very profitable to the souls in Purgatory, and constitute a suffrage of the greatest value. This is why I have permitted this soul, for her own sake and for the sake of others, to implore this of you. Know also that it was on account of your exactitude in practising this devotion that you have been favoured by frequent communication with the dead. It is for this reason also that those grateful souls never cease to pray for you, and to plead your cause at the tribunal of my Justice. Make known this treasure to your sisters, and tell them to draw from it abundantly for themselves and for the dead."
~ Excerpt from Purgatory: Illustrated by the Lives and Legends of the Saints
by Fr. Francis Xavier Shouppe, S.J. ~
A plenary indulgence can be gained once a day for praying the Way of the Cross
and the indulgence may be offered for the souls in Purgatory.
~ A related post on Indulgences ~