The Brahmin is born with three debts: he owes a debts to the sages, to the celestials and to the fathers. He repays the first by learning the Vedas as a student-bachelor; the second by taking a wife and performing sacrifices; and the third by begetting a son. So without marriage he cannot repay the second and third debts.
Sons are primarily intended for the repayment of the debts to the fathers. Performing the sraddha ceremony is not enough. Forefathers of the past three generations are to be made to ascend from the manes. So even after a man dies, for two generations the daily libations must be offered to him. That is why the birth of a son is considered important. (The case of the naisthika brahmacarin and the sannyasin is different. Because of their inner purity and enlightenment, they can liberate, not just two generations, but twenty-one generations of fathers without performing any sraddha ceremony).
[Hindu Dharma » Grhasthasrama » Grhastha and Grhini]
I'm specifically interested in the line marked in bold above.
Which Hindu scripture says that (naiṣṭhika) brahmacārīs and sannyāsīs can liberate souls of deceased parents and 21 generations of their ancestors without performing the śrāddha?
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