Matsyapurana 18.26

18.26

yāvadabdaṃ tu yo dadyād udakumbhaṃ vimatsaraḥ
pretāyānnasamāyuktaṃ so 'śvamedhaphalaṃ labhet //

The deceased, after living with the Pretas (spirits) for a long time, begins to feel uncomfortable. It is therefore necessary that Ekoddiṣṭa should be performed every year. One who, being devoid of jealousy, gives away a jar full of water along with grain for one full year, for the benefit of the departed spirit, has the same reward as is obtained by performing the Aśvamedha sacrifice.—25-26.