Srimad Bhagavatam Canto 11, Chapter 03, Text 45

SB 11.3.45

nacared yas tu vedoktam
svayam ajño ’jitendriyah
vikarmana hy adharmena
mrtyor mrtyum upaiti sah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
If an ignorant person who has not conquered the material senses does not adhere to the Vedic injunctions, certainly he will engage in sinful and irreligious activities. Thus his reward will be repeated birth and death.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
In the previous verse it was stated that although fruitive activities are prescribed in the Vedas, the actual goal of human life is to free oneself from all materialistic activities. Therefore, one may conclude that there is no need to perform the Vedic rituals, which offer regulated sense gratification. But an ignorant person, or, in other words, one who has not understood that he is not the material body but an eternal spiritual soul, part and parcel of Krsna, will invariably be unable to control the urges of the material senses. Therefore, if such a materially inclined person neglects the Vedic injunctions that administer regulated sense gratification, he will surely fall down into unregulated sense gratification in papa, or sinful life. For example, those who are affected by sexual desire are ordered to accept the vivaha-yajña, or religious marriage ceremony. We often see that because of false pride a so-called brahmacari, or celibate student of Vedic knowledge, rejects the marriage ceremony as maya, or material illusion. But if such a celibate student is unable to control his senses he will undoubtedly degrade himself by eventually engaging in illicit sex, which has no connection to Vedic culture. Similarly, a neophyte in Krsna consciousness is encouraged to eat krsna-prasadam to his full satisfaction. Sometimes an immature practitioner of bhakti-yoga tries to make a show of severe eating habits and eventually falls down into eating unregulated and abominable foodstuffs.
According to Srila Visvanatha Cakravarti Thakura, the words mrtyor mrtyum upaiti mean that a sinful person is awarded a free ticket to hell by the lord of death himself, Yamaraja. This is also described in the Vedas as follows: mrtva punar mrtyum apadyate ardyamanah sva-karmabhih. “Persons who cause themselves severe pain by their materialistic activities gain no relief at the moment of death, for they are placed again in a situation in which death will occur.” Therefore, Vedic ritualistic activities such as the wedding ceremony or the relishing of sumptuous yajña-sista, or food remnants of sacrifice, should not be given up by those whose senses are not yet controlled.
The previous verse gave the example of a father’s administering candy to his son to induce the child to take medicine. If the child rejects the father’s offer, thinking that the candy is unnecessary, the child also misses the opportunity to take the medicine that will cure him. Similarly, if a materialistic person rejects the Vedic injunctions that administer prescribed sense gratification, he will not be purified but instead will be further degraded. Srila Jiva Gosvami has described a materialistic person as one whose mind and intelligence are not faithfully fixed in the message of the Supreme Personality of Godhead. In Bhagavad-gita Sri Bhagavan, Lord Krsna, gives wonderful explanations to the conditioned souls, represented by Arjuna, concerning the actual goal of life. One who cannot fix his mind on these instructions is to be considered a materialistic person who is inclined toward sinful activities and who must therefore submit himself to the standard Vedic injunctions. Such Vedic injunctions, even though fruitive, are considered punya, or pious, according to Srila Jiva Gosvami, and thus one who strictly performs them will not go to hell. Lord Krsna Himself states in the Bhagavatam (11.20.9):
tavat karmani kurvita
na nirvidyeta yavata
mat-katha-sravanadau va
sraddha yavan na jayate
“One should continue to perform the Vedic ritualistic activities until one actually becomes detached from material sense gratification and develops faith for hearing and chanting about Me.”
Srila Visvanatha Cakravarti Thakura explains that the Vedas prescribe that one rise early in the morning, bathe, and chant the Gayatri mantra. If one artificially gives up such a disciplined, regulated life, one will gradually become a victim of activities for gross sense gratification, such as eating in restaurants and indulging in illicit connections with women. Thus losing control of his senses, he becomes just like an animal, engaging from the early morning until the night in dangerous activities. Srila Madhvacarya has commented in this regard, ajñah sann acarann api. Although in ignorance, one continues to act, not considering the future result of one’s activities. Such indifference to the future result of one’s activities is described in Bhagavad-gita to be a symptom of the mode of ignorance. Just as an intelligent man will not drive his car on a highway if he knows the highway will lead him to danger, an intelligent man will not perform non-Vedic activities if he knows that the ultimate result will be the disaster described here by the words mrtyor mrtyum upaiti. Srila Bhaktisiddhanta Sarasvati Thakura has stated that ignorant persons sometimes think that after death one automatically attains everlasting peace. But by the powerful reactions of one’s sinful activities one comes to a most unpeaceful condition, for one must suffer hellish miseries in exchange for the meager temporary fruits of material work. Such hellish reactions occur not once but perpetually, as long as one is indifferent to the Vedic injunctions.
Srimad Bhagavatam Canto 11, Chapter 03, Text 44
Srimad Bhagavatam Canto 11, Chapter 03, Text 46