Mbh 1.103.3a

“Vaisampayana continued, ‘Thus addressed by his mother and friends and relatives, that oppressor of foes, the virtuous Bhishma, gave this reply conformable to the dictates of virtue, ‘O mother, what thou sayest is certainly sanctioned by virtue. But thou knowest what my vow is in the matter of begetting children. Thou knowest also all that transpired in connection with thy dower. O Satyavati, I repeat the pledge I once gave, viz., I would renounce three worlds, the empire of heaven, anything that may be greater than that, but truth I would never renounce. The earth may renounce its scent, water may renounce its moisture, light may renounce its attribute of exhibiting forms, air may renounce its attribute of touch, the sun may renounce his glory, fire, its heat, the moon, his cooling rays, space, its capacity of generating sound, the slayer of Vritra, his prowess, the god of justice, his impartiality; but I cannot renounce truth.’ Thus addressed by her son endued with wealth of energy, Satyavati said unto Bhishma, ‘O thou whose prowess is truth, I know of thy firmness in truth. Thou canst, if so minded, create, by the help of thy energy, three worlds other than those that exist. I know what thy vow was on my account. But considering this emergency, bear thou the burden of the duty that one oweth to his ancestors. O punisher of foes, act in such a way that the lineal link may not be broken and our friends and relatives may not grieve.’ Thus urged by the miserable and weeping Satyavati speaking such words inconsistent with virtue from grief at the loss of her son, Bhishma addressed her again and said, ‘O Queen, turn not thy eyes away from virtue. O, destroy us not. Breach of truth by a Kshatriya is never applauded in our treatises on religion. I shall soon tell thee, O Queen, what the established Kshatriya usage is to which recourse may be had to prevent Santanu’s line becoming extinct on earth.