CC Madhya 22.36
yajeta puruṣaṁ param
akāmaḥ — a pure devotee with no desire for material enjoyment; sarva-kāmaḥ — one who has no end to his desires for material enjoyment; vā — or; mokṣa-kāmaḥ — one who desires to merge into the existence of Brahman; udāra-dhīḥ — being very intelligent; tīvreṇa — firm; bhakti-yogena — by devotional service; yajeta — should worship; puruṣam — the person; param — supreme.
“ ‘Whether one desires everything or nothing, or whether he desires to merge into the existence of the Lord, he is intelligent only if he worships Lord Kṛṣṇa, the Supreme Personality of Godhead, by rendering transcendental loving service.’
This is a verse from Śrīmad-Bhāgavatam (2.3.10).