All human beings must express their gratitude to their fathers (pitrs) and to the gods- they have a debt to pay their fathers, rites to perform for the gods. We must serve our fellow creatures to the best of our ability and extend hospitality at least to one guest a day. This is atithya or what Thiruvalluvar calls "virundu", also known as manusyayajna. Then there is Brahmayajna to perform, the word "Brahma" here denoting the Vedas. Brahmayajna means chanting the Vedas and making others chant them. This is a duty carried out by a few on behalf of all. One of the rites common to all is bhutayajna, demonstrating our love to all creatures, feeding them etc. Pitryajna, devayajna, manusyayajna, bhutayajana are rites all are duty-bound to perform in one way or. If each individual does his work according to the Vedic dharma and does it in a spirit of dedication to Isvara he may be said to be performing Brahmayajna. Thiruvalluvar has said more or less the same thing as the Vedas say:
Tenpulattar, deivam, virundu, okkal, tan enru angu
aimbulattaru ombal talai.
Tenpulattar are the pitrs, the fathers. All are duty-bound to pay their debt to them. Mother Veda says: "Matr-devo bhava, pitr-devo bhava. " (Be one to whom the mother is a deity. Be one to whom the father is a deity. ) Auvvai, who brings us the essence of the Vedas, observes: Annayum pitavum munnari deivam" [Mother and Father are the deities first known. ]
We must treat our parents with respect and do all we can to keep them in comfort. We cannot make sufficient recompense for all the sacrifices they make on our behalf. After they depart from this world we must without fail offer libations to them and perform the sraddha ceremony, all in the sastric manner. Though they ridicule the idea of performing sraddha, even reformers have agreed that we must care for our parents.
"The sesame you offer, the water, the balls of rice, the plantains and other items of food remain here," point out the reformists. "Or we see someone removing them before our own eyes, or eating them. You say that the departed parents are born again in this world. If that is true, is it not madness to claim that what is offered here will reach them?" Some of you must be harbouring similar doubts.
Let me tell you a story.
A certain man had sent his son to college in a distant town. One day the boy woke up to the fact that he had to pay his examination fee in a few days. So he wrote to his father: "Please send such and such a sum by telegraphic money order. " The father was a little perplexed. All the same he went to the telegraph office and handed the clerk at the counter the money that had to be sent to his son. "Please send it by telegraphic money order," he told the clerk. He had thought that the clerk would make holes in the notes, put a length of wire through them and send the whole thing to his son. Moments later the clerk said to the man: "Your son will get your money. It has already been sent. " The villager was again puzzled. He saw the money still in the cash box without the notes strung together. He told the clerk:"My money is still here. You haven't made holes in the notes yet." The clerk assured him: "It will reach your son." Now he turned to his work of sending messages: "Ka-tu-katu-katu." The poor village was still not satisfied.
But the money of course reached his son.
Offering libations to one's fathers is similar. If this rite is performed according to the sastras, the deities concerned will convey them to those for whom they are meant. If the fathers are reborn as cows the offering made to them will be taken to them in the form of grass or hay. The deities in charge carry out the orders of the Paramatman. So the father of the mother whose sraddha is performed need not personally come to receive the offering.
Does not the telegraphic money order reach the addressee? If the addressee resides in a foreign country our currency will not be valid there. If rupees are paid here arrangements are made to pay the money in dollars, pounds of whatever. The things offered to the fathers according to the sastras are conveyed in a form suitable to them.
What is important is a sense of gratitude to our fathers and faith in the sastras. At parties a toast is proposed to somebody and all the guests drink or eat to his health. They do so in the belief that by virtue of the mental power the man toasted will become healthy. Sraddha means that which is done in faith. Faith is of the utmost importance. If we do something we must do it according to the rules laid down for it. When you write a letter how do you make sure that it reaches the addressee? "I will write the address as I like. Why should I drop the letter in that letterbox over there? I have a better box at home." would you speak thus?
In the state of worklessness, love, devotion, and jnana are not bound by any rules. But when an action has a purpose behind it you have to respect the rules pertaining to it.
For a general background, please see here