It is stated in the Padma Purāṇa that there are four kinds of effects due to sinful activities, which are listed as follows: 1) the effect which is not yet fructified, 2) the effect which is lying as seed, 3) the effect which is already mature, and 4) the effect which is almost mature. It is also stated that all these four effects become immediately vanquished for those who surrender unto the Supreme Personality of Godhead, Viṣṇu, and become engaged in His devotional service in full Kṛṣṇa consciousness.
Those effects described as "almost mature" refer to the distress from which one is suffering at present, and the effects "lying as seed" means that in the core of the heart there is a certain stock of sinful desires which are like seeds. The Sanskrit word kūṭam means that they are almost ready to produce the seed, or the effect of the seed. An "immature effect" refers to the case where the seedling has not begun. From this statement of Padma Purāṇa it is understood that material contamination is very subtle. Its beginning, its fruition and results, and how one suffers such results in the form of distress, are part of a great chain. When one catches some disease, it is often very difficult to ascertain the cause of the disease, where it originated, and how it is maturing. The suffering of a disease, however, does not appear all of a sudden. It actually takes time. And, as in the medical field, for precaution's sake, the doctor injects a vaccination to prevent the growing of contamination, similarly, the practical injection to stop all the fructifications of the seeds of our sinful activities is simply engagement in Kṛṣṇa consciousness.
In this connection, Śukadeva Gosvāmī speaks in the Sixth Canto of Śrīmad-Bhāgavatam, 2nd Chapter, 17th verse, about the story of Ajāmila, who began life as a fine and dutiful brāhmaṇa but in his young manhood became wholly corrupted by a prostitute. At the end of his wicked life, just by calling the name of "Nārāyaṇa (Kṛṣṇa)," he was saved despite so much sin. Śukadeva points out that austerity, charity and the performance of ritualistic ceremonies for counteracting sinful activities are recommended processes, but that by performing them one cannot remove the sinful desire-seed from the heart, as was the case with Ajāmila in his youth. This sinful desire-seed can be removed only by achieving Kṛṣṇa consciousness. And this can be accomplished very easily by chanting the mahā-mantra, or Hare Kṛṣṇa mantra, as recommended by Śrī Caitanya Mahāprabhu. In other words, unless one adopts the path of devotional service, he cannot be one hundred percent clean from all the reactions of sinful activities.
By performing Vedic ritualistic activities, by giving money in charity and by undergoing austerity, one can temporarily become free from the reactions of sinful activities, but at the next moment he must again become engaged in sinful activities. For example, a person suffering from venereal disease on account of excessive indulgence in sex life has to undergo some severe pain in medical treatment, and he is then cured for the time being. But because he has not been able to remove the sex desire from his heart, he must again indulge in the same thing and become a victim of the same disease. So medical treatment may give temporary relief from the distress of such venereal disease, but unless one is trained to understand that sex life is abominable, it is impossible to be saved from such repeated distress. Similarly, the ritualistic performances, charity and austerity, which are recommended in the Vedas may temporarily stop one from acting in sinful ways, but as long as the heart is not clear, one will have to repeat sinful activities again and again.
Another example is given in the Śrīmad-Bhāgavatam of the elephant who enters into a lake and takes a bath very seriously, cleansing his body thoroughly. Then as soon as he comes onto shore he again takes some dust from the earth and throws it over his body. Similarly, a person who is not trained in Kṛṣṇa consciousness cannot become completely free from the desire for sinful activities. Neither the yoga process, nor philosophical speculations, nor fruitive activities can save one from the seeds of sinful desires. Only by being engaged in devotional service can this be done.