Agnihotra

H.H. Sri Swami Sivananda:

The Pitris remain in heaven, Pitri Loka or Chandra Loka, for a very long period. The enjoyments in heaven and the peace of the departed soul are enhanced by the performance of the Shraddha ceremony. Likewise the sufferings of the departed soul in worlds other than heaven are mitigated by the performance of the Shraddha ceremony by his sons. Thus, in both cases, the performance of Shraddha is a great help.
And even if the individual takes another birth immediately after his death, as happens in rare cases, the performance of Shraddha adds to his happiness in his new birth. So, it is the imperative duty of everybody to perform the Shraddha ceremony for his parents and forefathers. The Shraddha ceremony should be performed with great Shraddha or faith as long as you live. Faith is the main support for religion.
The various religious observances imposed upon mankind by the Shastras tend to purify the ignorant man. The Shraddha ceremony, being one of the obligatory duties as per the injunctions of the scriptures, also tends to purify the mind. Besides this, the forefathers are also pleased and their good wishes and blessings tend to our material and spiritual growth.

Swami Sivananda:

Scriptures, and the personages and episodes in the scriptures, are as true as God Himself. The former definitely and unambiguously say and propound that all the thirty crores of Devatas as envisaged in Hinduism have their abode in the frame of the cow, as in the Basil plant (Tulasi). The cow is boldly proclaimed in the scriptures as one of the objects of Dana (offering) for the uplift of the soul when the Prana departs from the body of a human being. The cow is really worthy of our adoration. Pancha Gavya (the milk, curd, Ghee, urine and dung of a cow) are ordained to be taken in for Prayaschitta at the commencement of certain Vratas like Rishi Panchami. Any number of instances can be cited regarding the holiness of a cow. Go-puja (cow worship) is as much fruitful as Sannyasi (Sadhu) Puja. It is equal to, if not more than, Sakala Devata Puja (worship of all deities). Such being the case, cow-slaughter (Go-Vadha) is condemnable without hesitation.