Bṛhad-bhāgavatāmṛta Part 2 Chapter 1 Text 62

bhagavantam ime viṣṇuṁ
nityaṁ vayam upāsmahe
guror gṛhīta-dīkṣākā
yathā-mantraṁ yathā-vidhiTRANSLATION
Initiated by our gurus, we always worship the Supreme Lord Viṣṇu with the mantras and methods they have given us.