"809 During the night, I was suddenly awakened and knew that some soul was asking me for prayer, and that it was in much need of prayer. Briefly, but with all my soul, I asked the Lord for grace for her.
810 The following afternoon, when I entered the ward, I saw someone dying, and learned that the agony had started during the night. When I verified it-it had been at the time when I had been asked for prayer. And just then, I heard a voice in my soul: Say the chaplet which I taught you. I ran to fetch my rosary and knelt down by the dying person and, with all the ardour of my soul, I began to say the chaplet. Suddenly the dying person opened her eyes and looked at me; I had not managed to finish the entire chaplet when she died, with extraordinary peace. I fervently asked the Lord to fulfill the promise He had given me for the recitation of the chaplet. The Lord gave me to know that the soul had been granted the grace He had promised me. That was the first soul to receive the benefit of the Lord's promise. I could feel the power of mercy envelop that soul.
811 When I entered my solitude, I heard these words: At the hour of their death, I defend as My own glory every soul that will say this chaplet; or when others say it for a dying person, the indulgence is the same. When this chaplet is said by the bedside of a dying person, God's anger is placated, unfathomable mercy envelops the soul, and the very depths of My tender mercy are moved for the sake of the sorrowful Passion of My Son.
Oh, if only everyone realized how great the Lord's mercy is and how much we all need that mercy, especially at that crucial hour!"
If you're not familiar with it, you can find the Chaplet and how to say it here.