All should treat an Atithi (guest, stranger or anyone who comes to you for help or support) with due respect. The word Atithi simply means one who comes at an unspecified or unfixed time. Thus anyone who comes to you abruptly or comes for food or water should be welcomed. Here Shatanand explains that Atithi corresponds to a ‘Bhikshuka’.
Skanda Purana explains, ‘The following six are Dharma Bhikshukas: (1) one who crosses your path, (2) somebody who is weak, (3) a student, (4) one who looks after a Guru, (5) a Sanyasin (renounced person) and (6) a Brahmchari (celibate).’ Thus such persons should be given food and water and welcomed according to one’s ability.
Shatanand explains - Abhyarchaha Abhivandanpurvakam Santoshariya Ityartha - they should be made welcome by greeting such person with Namaskar. Kashi Khanda explains, ‘The Punya obtained by donating cows (Godaan) is obtained by merely according a warm welcome to a Bhikshuka and offering food, water, shelter and the like.’
Parashar Smruti explains, ‘Those who have welcomed an Athithi with love have pleased God.’ Shrimad Bhagwat also explains, ‘Those houses, whose water, door mat, land, owner and servants have entertained righteous men - even though they are poor, are lucky as they are destined for fortune.’ It is also said there, ‘Houses that have never been blessed by the dust from the feet of God’s Bhaktas are no more than mere trees for snakes to reside within, even though such houses may be prosperous with fortune.’
‘Those houses that have never offered even water to Atithis are like houses frosted over by the cold season.’ ‘Those who do not welcome Atithis are consigned to Paryavartan hell, where they are subjected to such intense pains as having their eyes pierced by birds.’ ‘Those Atithi who leave without proper welcome take away with them the Punya accrued by that household.’ Shanti Parva explains, ‘Even one’s enemy should be welcomed, should he come for shelter.’
Secondly, rites pertaining to Gods - Deva Karma should be performed to Brahma and other Gods. Tarpana (ceremonial offerings of water), Vaishvadeva and other such rituals should be performed. Similarly, rites pertaining to one’s ancestors - Pitru Karma should be performed. These include Tarpana and Shraadh.
These Pitru Karmas should be performed according to whether ones father has passed away or is living and according to the health of their father. Smruti explains, ‘Those with foolish intellect, who do not perform Deva and Pitru Karmas according to their wealth will without a doubt, end up in Rairav Narak (a particular type of hell).’
In general terms, Deva Karma includes Poojan and is performed in order to please God. Shraadh is derived from the word Shraddha (faith). Therefore it is the act of offering something with faith to one’s ancestors. By so doing, the ancestors receive the fruits of such action and in return we receive their blessings.
Therefore by performing such rituals or by donating money in the name of parents/forefathers, the fruits of such action is reaped by the ancestor giving them a better future in the after world and we are given blessings by them which will benefit us in this world.