Bhagavad Gita 12.20
Verily, those who love the spiritual wisdom as I have taught, whose faith never wavers, and who focus their entire being on Me, they are indeed My most beloved.
ये तु धर्म्यामृतमिदं यथोक्तं पर्युपासते।श्रद्दधाना मत्परमा भक्तास्तेऽतीव मे प्रियाः॥ye tu dharmyāmṛtamidaṃ yathoktaṃ paryupāsate|śraddadhānā matparamā bhaktāste'tīva me priyāḥ||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).