Shloka 138
ज्येष्ठ-कनिष्ठ-धर्मः — Duties of Elders and Juniors
Anuśāsana-parva 108
अनायुष्यं दिवा स्वप्न तथाभ्युदितशायिता । प्रगे निशामाशु तथा नैवोच्छिष्टा: स्वपन्ति वै
anāyuṣyaṃ divā svapnaḥ tathābhyuditśāyitā | prage niśām āśu tathā naivocchiṣṭāḥ svapanti vai ||
ビーシュマは言った。「昼に眠り、また日の出の後に横たわって眠ることは寿命を減ずる。暁には眠ってはならず、夜の初めにも眠ってはならぬ。行い正しき者は、夜に不浄のまま（食後に身を清めぬまま）眠らない。」
भीष्म उवाच
Educational Q&A
Bhishma teaches disciplined daily conduct: avoid daytime sleep and sleeping after sunrise, do not sleep at dawn or at the start of night, and maintain bodily/ritual cleanliness—especially not sleeping at night while ‘ucchiṣṭa’ (uncleansed after eating).
In the Anushasana Parva’s instruction on dharma and proper conduct, Bhishma continues giving Yudhishthira practical ethical guidance (ācāra) about daily routines—here, specifically regulating sleep and emphasizing purity.