For one engaged in pure devotional service, such as core ISKCON activities, or being in the true spirit of core ISKCON activities, there is no need to engage in other forms of ritual, penance, meditation, or `spiritual strivings.' A nice verse and purport in Srila Prabhupada's Srimad Bhagavatam explains this nicely: It is in the 2nd Canto, Seventh Chapter. The text is number forty-eight. This is Srila Prabhupada's translation: "In such a transcendental state there is no need of artificial control of the mind, mental speculation or meditation, as performed by the jnanis and yogis. One gives up such processes, as the heavenly King, Indra, forgoes the trouble to dig a well."
And this is his purport: "King Indra of heaven is the controlling deity or demigod for arranging clouds supplying rains in the universe, and as such he does not have to take he trouble to dig a well for his personal water supply. For him, digging a well for a water supply is simply ludicrous. Similarly, those who are factually engaged in the loving service of the Lord have attained the ultimate goal of life, and for them there is no need of mental speculation to find out the true nature of God or His activities. Nor do such devotees have to meditate upon the imaginary or real identity of the Lord. Because they are factually engaged in the transcendental loving service of the Lord, the Lord's pure devotees have already achieved the results of mental speculation and meditation. The real perfection of life is therefore to be engaged in the transcendental loving service of the Lord."