Of course, by hearing, it will be purified. We have to help. Help means to avoid the offenses, ten kinds of offenses. So in this way we shall help the purificatory process. Just like if I want to ignite fire, so I must help the igniting process by drying the wood. It will very soon get fire. Similarly, simply chanting, that will help us also. It will take time. But if we avoid the offenses, then it will be very quickly purified. The action will be there.
So ataḥ śrī-kṛṣṇa-nāmādi na bhaved grāhyam indriyaiḥ (CC Madhya 17.136). So this behavior of Kṛṣṇa, how ordinary men can understand? Because they have got their ordinary senses, therefore they mistake. Why Kṛṣṇa? Even Kṛṣṇa's devotee, Vaiṣṇava. That is also stated. Vaiṣṇavera kriyā mūdra vijñeha nā bujhaya (CC Madhya 23.39). Even a Vaiṣṇava ācārya, what he is doing, even the most expert intelligent man cannot understand why he is doing this.