Shree Krishna has said in the Bhagwatam,
कथं विना रोमहर्षं द्रवता चेतसा विना ।
विनानन्दाश्रुकलया शुध्येद् भक्त्या विनाशय: ॥Kathaṁ vinā romaharṣhaṁ dravatā chetasā vinā.
Vinānandāśhru-kalayā śhudhyed bhaktyā vināśhayaḥ.- Bhagwatam 11.14.23
He says, “Just physical worship of Me will not purify your heart. You have to be emotionally engaged. You have to love Me. Your heart should melt for Me.”
‘Kathaṁ vinā roma-harṣaṁ’ means that ‘you should feel a thrill when you think of Me’, Shree Krishna says. ‘Dravatā’ means ‘your heart should melt when you remember Me’ - dravatā chetasā vinā.
‘Vinānandāśhru-kalayā’ means ‘you should have tears of love and longing for Me when you think of Me’.
See, Shree Krishna is telling us how to do devotion.
The Shvetashvatar Upanishad also says, “You have to love God, not just go through the motions of physical devotion.”
नयनं गलदश्रुधारया वदनं गद्गदरुद्धया गिरा ।
पुलकैर्निचितं वपुः कदा तव नामग्रहणे भविष्यति ॥Nayanaṁ galad-aśhru-dhārayā vadanaṁ gadgada-ruddhayā girā.
Pulakair nichitaṁ vapuḥ kadā tav nām-grahaṇe bhaviṣhyati.- Shikshashtakam 6
Chaitanya Mahaprabhu Ji also says that it’s not enough just to chant the names of Radha Krishna. He says,
“When will that day come that, while I’m chanting Your name, tears will come to my eyes, my throat will choke with emotion, and my body will tremble with excitement in thinking of You? When will that day come?”
