One cannot be situated in the devotional service of the Lord unless one is free from sinful life. This is confirmed in the Bhagavad-gita (7.28):

"Persons who have acted piously in previous lives and in this life and whose sinful actions are completely eradicated are freed from the duality of delusion, and they engage themselves in My service with determination." A person who is already cleansed of all tinges of sinful life engages without deviation or duality of purpose in the transcendental loving service of the Lord. In this age, although people are greatly sinful, simply chanting the Hare Krsna maha-mantra can relieve them from the reactions of their sins. Eka krsna-name: only by chanting Krsna's name is this possible. This is also confirmed in Srimad-Bhagavatam (kirtanad eva krsnasya). Caitanya Mahaprabhu has also taught us this. While passing on the road, He used to chant:

If one always chants the holy name Krsna, gradually one is freed from all reactions of sinful life, provided he chants offenselessly and does not commit more sinful activities on the strength of chanting the Hare Krsna mantra. In this way one is purified, and his devotional service causes the arousal of his dormant love of God. Simply by chanting the Hare Krsna mantra and not committing sinful activities and offenses, one's life is purified, and thus one comes to the fifth stage of perfection, or engagement in the loving service of the Lord (prema pum-artho mahan).