Mahabharata is a famous epic describing diverse aspects of human life, like family and its intrigues, kingship, loyalty, friendship, dharma, war, Vedantic teaching, etc. Bhagavat Gita is in the 12th Book named Bhisma Parva because Bhisma is the commander of the Kauravas army during this part. 18 chapters of BG are chapters 23 to 40 of Bhisma Parva. BG is a moksha shastra and a student of Vedanta should have read and understood Bhagavat Gita fairly well. Surprisingly, there are other portions of Mahabharata that too have Vedantic teaching. Mokshadharma Parva as the title suggests has Vedantic messages. It is a conversation between Yudhishthira and Bhisma.
After the Mahabharata war is over, Bhisma is lying on the bed of arrows awaiting his death to come at a time chosen by him. Yudhishthira is the new king but is depressed due to the destruction caused by the war. At the behest of Sri Krishna, he visits Bhisma to get instructions on various topics. Bhisma, though lying on the bed of arrows, is willing to answer Yudhishthira’s questions. He does so mainly through stories. One such story in Mokshadharma parva relates to the teaching given by a son to his father.
Yudhishthira realizes that time is the ultimate destroyer of every created thing and he requests Bhisma to teach him the highest good to be sought for. Bhisma narrates a story in the form of spiritual teaching given by an intelligent son Medhavi to his father devoted to studying Vedas. Medhavi is a spiritual seeker and is worried that human life is passing away quickly. He, therefore, asks his father to tell him what should a wise person do and how should he discharge his duties and the fruits thereof. Medhavi desires to observe such duties as described by his father. The father explains the traditional four ashrams(stages) of life, namely, brahmacharya, grihastha, vanaprastha, and sannyasa, and their duties prescribed in the scriptures. Brahmcharya is for the study of Vedas, leading a family life in grihastha ashrama, and gradually withdrawing from worldly life in vanaprastha. In the final sannyasa ashrama, a person should live a secluded forest life devoting the rest of life to spiritual contemplation for the attainment of moksha.
On his father speaking so, Medahvi is surprised to note that his father has not given due consideration to the fact that everyday life gets shorter. The son questions his father for his casual reply in view of the stark reality that worldly life is constantly beset with suffering. The father asks his son to explain his pessimism in detail. Medhavi says that death is lurking all the time. It does not spare anyone and with each passing night, human life becomes shorter. In this view how can he pass his time without being suitably shielded? As death steadily approaches, a person cannot be happy like a fish that is not happy in shallow water. Nobody knows when death will hit. It may come before one’s desires are fulfilled. It may come when a person is busy plucking flowers like a sheep busy grazing blades of grass is attacked by a wolf. Attached with family and cattle like a tiger taking an animal, death may surprise him. It may come even today. Therefore, one should accomplish good in life today before becoming death’s victim. Tomorrow’s work should be done today, afternoon’s work in the forenoon. Cruel death does not see whether the goals of its victim are accomplished or not.
Medhavi teaches his father that in view of the uncertain nature of life, spiritual practices for moksha should not be postponed till sannyasa ashrama as suggested by his father. According to Medhavi, one should begin seeking Truth without loss of time so as to conquer death. Two courses are possible, death and immortality. Ignorance leads to death and truth leads to immortality. A wise person begins preparation for spirituality in the prime of age. An unwise person is busy otherwise. He forgets that death may strike him in the midst of worldly happiness and even while he is mulling over his finished, half-finished, and unfinished plans.
Bhisma advises Yudhishthira to conduct himself in the manner in which the father would conduct after hearing his son Medhavi.