prabhu kahena — the Lord replied; kṛṣṇa-sevā — serving Kṛṣṇa; vaiṣṇava-sevana — abiding by the orders of Vaiṣṇavas; nirantara — without cessation; kara — do; kṛṣṇa-nāma-saṅkīrtana — chanting of the holy name of Lord Kṛṣṇa.