“The nine different processes enunciated by Prahlada Maharaja, who learned them from Narada Muni, may not all be required for the execution of devotional service; if a devotee performs only one of these nine without deviation, he can attain the mercy of the Supreme Personality of Godhead.” (Shrila Prabhupada, Shrimad Bhagavatam, 7.5.23-24)