Our ancestors are those with whom we share strong patterns of consciousness and energy. We have different names for this patterning: our bodies, our habitual activities and our habitual emotions. The nearer ancestors are to us, the more habitual patterning, or karma, we share.
The purpose of performing a daily ancestor puja is twofold. First, we communicate to our ancestors our gratitude for our human lives. Second, we state the intention to benefit our ancestors through our activities in this life. Each of these is an act of kindness, and kindness is the universal medicine for suffering.
Kindness is the offering that contributes most to the relaxation and realization of your ancestors, yourself and all beings. Kindness is literally the recognition of all beings as your kin.