Mahabharata 2.38.28

2.38.28

so'napatyaśca vṛddhaśca mithyādharmānuśāsanāt |
haṃsavattvamapīdānīṃ jñātibhyaḥ prāpnuyā vadham || 28 ||

The merit, O Bhishma, that is acquired by numberless vows and fasts assuredly becomes fruitless in the case of one that is childless. Thou art childless and old and the expounder of false morality. Like the swan in the story, thou shalt now die at the hands of thy relatives. Other men possessed of knowledge have said this of old. I will presently recite it fully in thy hearing.