The duty of a son is to perform the sraddha ritualistic ceremony after his father's death so that his father may be promoted to a planetary system where he may become a good citizen and devotee

Expressions researched:
"the duty of a son is to perform the śrāddha ritualistic ceremony after his father's death so that his father may be promoted to a planetary system where he may become a good citizen and devotee"

Srimad-Bhagavatam

SB Canto 7

Nonetheless, the duty of a son is to perform the śrāddha ritualistic ceremony after his father's death so that his father may be promoted to a planetary system where he may become a good citizen and devotee.

SB 7.10.22, Translation and Purport

My dear child, your father has already been purified just by the touch of My body at the time of his death. Nonetheless, the duty of a son is to perform the śrāddha ritualistic ceremony after his father's death so that his father may be promoted to a planetary system where he may become a good citizen and devotee.

In this regard, Śrīla Viśvanātha Cakravartī Ṭhākura says that although Hiraṇyakaśipu was already purified, he had to take birth on a higher planetary system to become a devotee again. Prahlāda Mahārāja was advised to perform the ritualistic ceremony as a matter of etiquette, for the Supreme Personality of Godhead under no circumstances wants to stop the regulative principles. Madhva Muni also instructs:

madhu-kaiṭabhau bhakty-abhāvā

dūrau bhagavato mṛtau

tama eva kramād āptau

bhaktyā ced yo hariṁ yayau

When the demons Madhu and Kaiṭabha were killed by the Supreme Personality of Godhead, their kinsmen also observed the ritualistic ceremonies so that these demons could return home, back to Godhead.