The Happiness of Becoming One with the Supreme (it is from Nectar of Devotion)
Śrīla Rūpa Gosvāmī says that if brahmānanda, or the happiness of becoming one with the Supreme, is multiplied by one trillionfold, it still cannot compare to an atomic fraction of the happiness derived from the ocean of devotional service.
In the Hari-bhakti-sudhodaya Prahlāda Mahārāja, while satisfying Lord Nṛsiḿhadeva by his prayers, says, "My dear Lord of the universe, I am feeling transcendental pleasure in Your presence and have become merged in the ocean of happiness. I now consider the happiness of brahmānanda to be no more than the water in the impression left by a cow's hoof in the earth, compared to this ocean of bliss." Similarly, it is confirmed in the Bhāvārtha-dīpikā, Śrīdhara Svāmī's commentary on the Śrīmad-Bhāgavatam, "My dear Lord, some of the fortunate persons who are swimming in the ocean of Your nectar of devotion, and who are relishing the nectar of the narration of Your pastimes, certainly know ecstasies which immediately minimize the value of the happiness derived from religiousness, economic development, sense gratification and liberation. Such a transcendental devotee regards any kind of happiness other than devotional service as no better than straw in the street."