Śrī Caitanya Caritamrta · Text Ādi 4.177
কৃষ্ণের প্রতিজ্ঞা এক আছে পূর্ব হৈতে ।
যে যৈছে ভজে, কৃষ্ণ তারে ভজে তৈছে ॥ ১৭৭ ॥
kṛṣṇera pratijñā eka āche pūrva haite
ye yaiche bhaje, kṛṣṇa tāre bhaje taiche
Lord Kṛṣṇa has a promise from before to reciprocate with His devotees according to the way they worship Him.
Read this verse on Vedabase.ioThis verse has no purport; its meaning is explained by the verses around it.