Viṣṇudūta says that, "We know that this person was addicted to sinful activities throughout his whole life, but at the time of his death he has remembered. He has uttered offenselessly once the name of Nārāyaṇa." But one should not think that, "All right. Let us go on committing all sinful activities, and at the time of my death I shall think of Nārāyaṇa or Kṛṣṇa." That is not possible.
That is explained in the Bhagavad-gītā. If you practice when you are alive, when you are strong, for chanting the holy name of Kṛṣṇa or Nārāyaṇa, then there may be chance. Otherwise it is not possible. Not that a layman will all of a sudden will chant "Nārāyaṇa." He must have previous practice. Therefore Caitanya Mahāprabhu has recommended, kīrtanīyaḥ sadā hariḥ (CC Adi 17.31). Amāninā mānadena kīrtanīyaḥ sadā hariḥ. Sadā tad-bhāva-bhāvitaḥ. In the Bhagavad-gītā Śrī Kṛṣṇa says, sadā tad-bhāva-bhāvitaḥ (BG 8.6). If you practice in your life chanting the holy name of Kṛṣṇa . . .
I remember one of our teachers in our school life, he instructed that, "If you always think that, 'I shall pass my examination with distinction,' then you can pass in first division. If you think that 'I shall pass my examination in the first division,' then you may pass in the third division. And if you think that, 'I shall some way pass my examination in the third division,' then you will fail." That means if you expect more than your capacity, then it may be possible that at the time of examination you get the right number and pass your exam.