Śvetadvīpa-varṇana and Śāstra-pravartana (Śānti Parva 322)
बालो युवा वा वृद्धश्च यत् करोति शुभाशुभम् । तस्यां तस्यामवस्थायां भुड्धक्ते जन्मनि जन्मनि
bālo yuvā vā vṛddhaś ca yat karoti śubhāśubham | tasyāṃ tasyām avasthāyāṃ bhuṅkte janmani janmani ||
बालो युवा वा वृद्धश्च यत् करोति शुभाशुभम् । तस्यां तस्यामवस्थायां भुङ्क्ते जन्मनि जन्मनि ॥
भीष्म उवाच
Karmic accountability is precise: deeds—good or bad—bear fruit across repeated births, and the experience of that fruit corresponds to the life-stage in which the deed was performed.
In the Shanti Parva’s instruction on dharma and conduct, Bhishma teaches about karma and its results, emphasizing that actions done in childhood, youth, or old age return with appropriate consequences over successive births.