11 To be effective, chanting should be accompanied by the four regulative principles
The chanting of the Hare Krsna mantra will be effective if accompanied by the austerity of giving up the four sinful activities:
[Sukadeva Gosvami to King Pariksit]: For a few months the sons of Prajapati Daksa drank only water and ate only air. Thus undergoing great austerities, they recited this mantra: "Let us offer our respectful obeisances unto Narayana, the Supreme Personality of Godhead, who is always situated in His transcendental abode. Since He is the Supreme Person [Paramahamsa], let us offer our respectful obeisances unto Him."
From these verses it is apparent that the chanting of the mahamantra or the Vedic mantras must be accompanied by severe austerities. In Kali−yuga, people cannot undergo severe austerities like those mentioned herein−drinking only water and eating only air for many months. One cannot imitate such a process. But at least one must undergo some austerity by giving up four unwanted principles, namely illicit sex, meat−eating, intoxication and gambling. Anyone can easily practice this tapasya, and then the chanting of the Hare Krsna mantra will be effective without delay. One should not give up the process of austerity.
– Srimad Bhagavatam 6.5.27−28
