The regular rhythms of life cease when someone close to us dies. The age-old custom of remembering the souls of the departed and contributing to charity in their memory is embedded in the fundamental Jewish belief in the everlastingness of the soul.  The Yizkor service is said on Yom Kippur.  When a person passes onto the next world, the Soul can no longer do good deeds to attain merit. But despite the apparent finality of the closing of their book of deeds, when we give charity, do good deeds, or say a prayer, this indeed can achieve spiritual elevations, and open the ledger for a rectification of merits for the deceased. Similarly, the Yizkor service can reopen the book of deeds and bring merit and elevation to your loved ones.  Adonai treats our prayer and our charity as if the deceased gave it.  For if not for them, the noble act would not have taken place.