In Kali−yuga, one can attain the same results attained in previous ages by severe austerities by chanting the Hare Krsna mantra: Although Dhruva Maharaja was only a five−year−old boy, he underwent severe austerities by eating simply dry foliage, drinking only water and taking no food. In this way, after six months, he was able to see the Supreme Personality of Godhead face to face.
When he saw the Lord, he forgot all his austerities and said, svamin krtartho 'smi: "My dear Lord, I am very pleased." Of course, these austerities were performed in the Satya−yuga, Dvapara−yuga and Treta−yuga, but not in this age of Kali. In this Kali−yuga, one can attain the same results simply by chanting the Hare Krsna maha−mantra. Because the people of this age are fallen, the Lord is kind enough to give them the easiest method. Simply by chanting the Hare Krsna mantra, one can attain the same results.
¯Srimad−Bhagavatam 4.30.4