One may think that because he is surrendering unto the Supreme Personality of Godhead he will not be able to perform all of his other obligations. But the Lord says repeatedly, "Don't hesitate. Don't consider that because you are giving up all other engagements there will be some flaw in your life. Don't think like that. I will give you all protection." That is the assurance of Lord Kṛṣṇa in Bhagavad-gītā.
There is additional evidence in the Agastya-saṁhitā: "As the regulative principles of scripture are not required by a liberated person, so the ritualistic principles indicated in the Vedic supplements are also not required for a person duly engaged in the service of Lord Rāmacandra." In other words, the devotees of Lord Rāmacandra, or Kṛṣṇa, are already liberated persons and are not required to follow all the regulative principles mentioned in the ritualistic portions of the Vedic literature.