SB 10.51.55

na kāmaye ’nyaṁ tava pāda-sevanād
 akiñcana-prārthyatamād varaṁ vibho
ārādhya kas tvāṁ hy apavarga-daṁ hare
 vṛṇīta āryo varam ātma-bandhanam
Word for word: 
na kāmaye — I do not desire; anyam — another; tava — Your; pāda — of the feet; sevanāt — than the service; akiñcana — by those who want nothing material; prārthya-tamāt — which is the favorite object of entreaty; varam — boon; vibho — O all-powerful one; ārādhya — worshiping; kaḥ — who; tvām — You; hi — indeed; apavarga — of liberation; dam — the bestower; hare — O Lord Hari; vṛṇīta — would choose; āryaḥ — a spiritually advanced person; varam — boon; ātma — his own; bandhanam — (cause of) bondage.
Translation: 
O all-powerful one, I desire no boon other than service to Your lotus feet, the boon most eagerly sought by those free of material desire. O Hari, what enlightened person who worships You, the giver of liberation, would choose a boon that causes his own bondage?
Purport: 

The Lord offered Mucukunda anything he desired, but Mucukunda desired only the Lord. This is pure Kṛṣṇa consciousness.