CC Ādi 6.30

vaiṣṇavera guru teṅho jagatera ārya
dui-nāma-milane haila ‘advaita-ācārya’
Word for word: 
vaiṣṇavera — of the devotees; guru — spiritual master; teṅho — He; jagatera ārya — the most respectable personality in the world; dui-nāma-milane — by combining the two names; haila — there was; advaita-ācārya — the name Advaita Ācārya.
Translation: 
He is the spiritual master of all devotees and is the most revered personality in the world. By a combination of these two names, His name is Advaita Ācārya.
Purport: 

Śrī Advaita Ācārya is the prime spiritual master of the Vaiṣṇavas, and He is worshipable by all Vaiṣṇavas. Vaiṣṇavas must follow in the footsteps of Advaita Ācārya, for by so doing one can actually engage in the devotional service of the Lord.