Śrī Caitanya Caritamrta · Text Madhya 23.100
সর্বথৈব দুরূহোঽয়মভক্তৈর্ভগবদ্রসঃ ।
তৎপাদাম্বুজসর্বস্বৈর্ভক্তৈরেবানুরস্যতে ॥ ১০০ ॥
sarvathaiva durūho ’yam
abhaktair bhagavad-rasaḥ
tat pādāmbuja-sarvasvair
bhaktair evānurasyate
“ ‘Nondevotees cannot understand the exchange of transcendental mellows between the devotees and the Lord. In all respects, this is very difficult to understand, but one who has dedicated everything to the lotus feet of Kṛṣṇa can taste the transcendental mellows.’
Read Śrīla Prabhupāda's purport on Vedabase.io