Srimad Bhagavatham 7:7:52
न दानं न तपो नेज्या न शौचं न व्रतानि च ।
प्रीयतेऽमलया भक्त्या हरिर् अन्यद् विडम्बनम् ॥
Neither charity, nor penance, neither sacrifice nor purificatory rites and vows can one satisfy Lord Hari. He can be satisfied with pure devotion alone and all other practices are ostentation.
Please check these: Excerpts from a discourse by our Sri Sri Muralidhara Swamiji
I can worship God, but how can I love LORD KRISHNA? You can love Him if you understand that Sri Krishna is pure love and love alone.In order to realize that you have to continuously chant the Maha Mantra.