तथैव द्वादशसमा: कपाली ब्रह्महा भवेत् । ब्रह्मचारी भवेन्नित्यं स्वकर्म ख्यापयन् मुनि:
tathaiva dvādaśa-samāḥ kapālī brahmahā bhavet | brahmacārī bhaven nityaṃ svakarma khyāpayan muniḥ ||
Bhīṣma said: “In the same way, for twelve years he should live as a skull-bearing ascetic; he is to be regarded as one who has incurred the sin of brahmin-slaying. He should remain ever a celibate religious student, and, as a sage, openly acknowledge and make known his own deed (and the penance undertaken for it).”
भीष्म उवाच
Grave wrongdoing requires sustained, disciplined expiation: adopting austere marks of penance (kapālī), maintaining lifelong-like restraint (brahmacarya during the vow), and honestly acknowledging one’s deed rather than concealing it.
In Bhīṣma’s dharma-instruction during the Śānti Parva, he outlines a specific expiatory regimen for the sin of brahmin-slaying: a twelve-year skull-bearing ascetic observance combined with continual celibacy and public avowal of the act and the penance.