CC Antya 4.79

bhakta-bhakti-kṛṣṇaprema-tattvera nirdhāra
vaiṣṇavera kṛtya, āra vaiṣṇava-ācāra
Word for word: 
bhakta — devotee; bhakti — devotional service; kṛṣṇa-prema — love of Kṛṣṇa; tattvera — of the truth of; nirdhāra — ascertainment; vaiṣṇavera kṛtya — duties of a Vaiṣṇava; āra — and; vaiṣṇava-ācāra — characteristics of a Vaiṣṇava.
Translation: 
“You shall have to ascertain the basic principles of a devotee, devotional service, love of Godhead, Vaiṣṇava duties and Vaiṣṇava characteristics.