Caitanya-caritāmṛta 3.21
āpane nā kaile dharma śikhāna nā yāya ei ta’ siddhānta gītā-bhāgavate gāya
[aapane naa kaile dharma shikhaana naa yaaya ei ta’ siddhaanta geetaa-bhaagavate gaaya]
Blended reading (Sanskrit + English inline)
āpane nā kaile dharma śikhāna nā yāya ei ta’ siddhānta gītā-bhāgavate gāya
“Unless one practices devotional service himself, he cannot teach it to others. This conclusion is indeed confirmed throughout the Gītā and Bhāgavatam.
My note
Source: vedabase.io