Grihya Sutra forms a part of Kalpa Sutras, which are aphoristic texts concerned with rituals and moral codes. In Hindu religion, Grihya Sutra deals with domestic rituals – household pujas and other rules. Within this Kalpa literature, Srauta Sutra covers major public sacrifices, while Grihya Sutra treats those ceremonies applicable from birth to death, performed by the married householder.
Sutras were auxiliary literature of Vedic scriptures, composed in brief, cryptic phrases designed as reminders for extensive collections of oral traditions. Thus Kalpa Sutras (rules, prescriptions) deals with rites and rituals, and Grihya Sutra (household) comprises the domestic portion of the literature.
Domestic rituals are performed with only one household fire, kindled ritually and used for all household ceremonies. The Srauta rites require three fires – Garhapatya Agni, dakshin agni and avahaniyagni (fire kindled by friction and deposited in separate places).
The public Srauta ceremonies are performed by those of Brahmin descent.
The domestic rituals are performed by all those who have been initiated into the study of the Vedic scriptures.
Grihya Sutra prescribes domestic sacraments to be performed by the husband in the company of his wife with garhapatya agni (the household fire).
They describe forty consecrations, of which eighteen are bodily sacraments, such as prenatal and postnatal ceremonies, first feeding of the child, initiation into scriptural study, marriage rites and the like.
Among the other rites are the five daily ritual offerings, i.e., pancha maha yajnas, Deva yajna (offerings to the gods), Bhuta Yajna (offerings to the spiritual essences of the five elements), Pitr Yajna (offerings to the ancestors), Brahma Yajna (recitation of Vedas) and Manushya Yajna (offerings to human persons), such as hospitality to guests before having one’s meals.
There are also new and full moon rituals, and other periodic rites.
Grihya Sutra shows detailed funeral rites and rules to the followed for postmortem rites, as well as the monthly and annual oblations to the ancestors.
Source –
Vedic Rituals – In The Cultural Heritage Of India Vol.1 Kolkata (1958) by V.M. Apte - The Ramakrishna Mission Institute of Culture
The Grihyasutras (1886) by H Oldenberg – Oxford University Press
Encyclopedia of Hinduism Volume IV page 366 – 367 - IHRF