Mahabharata — Anushasana Parva, Shloka 14
अत्रेः तपोबलप्रकाशः तथा च्यवनस्य सोमाधिकारः
Atri’s Illumination by Tapas; Cyavana and Soma-Entitlement
इत्यर्थमपराह्ले तु पितृणां श्राद्धमुच्यते । यथोक्तानां यदश्नीयुरत्रल्यिणा: पूर्वकीर्तिता:
ity artham aparāhṇe tu pitṝṇāṁ śrāddham ucyate | yathoktānāṁ yad aśnīyur atralyiṇāḥ pūrvakīrtitāḥ ||
毗湿摩说道：“正因如此，为诸祖灵（Pitṛs）所行的施罗陀（śrāddha）被规定在午后举行。如此，先前所述那些合宜而具足资格之人，便能依所说之法受食。”
भीष्य उवाच
Educational Q&A
Śrāddha for the ancestors is to be performed in the afternoon (aparāhṇa), so that duly qualified recipients can partake according to the prescribed rules; correct timing supports ritual propriety and purity.
In the Anuśāsana Parva’s instruction on dharma, Bhīṣma continues advising on śrāddha procedure, explaining why the rite is scheduled for the afternoon and linking it to the proper feeding of qualified participants.