Srimad Bhagvata Mahapurana: Book 8: Chapter 23: Verses 1-14
Freed from bondage, Bali enters the region of Sutala
Sri Suka resumed : To Lord Visnu (the most ancient Person in the disguise of a dwarf), who had spoken thus, the magnanimous Bali, who was esteemed by all pious souls, submitted with joined palms and in a faltering voice (as follows), his eyes dimmed with drops of tears and his throat choked (with emotion). Ball said : Oh, a (mere) sincere effort made to bow low (at Your feet) is (found) intent on (capable of) securing (even to people like me, who can never claim to be Your devotees) the boon sought for by devotees that have sought You (for protection). For by that (very) endeavour has been vouchsafed to a vile demon (full of Rajas like me)that (unique) favour of Yours which was never obtained before (even) by the guardians of the (various) worlds and (other) gods (who are eminently Sattvika by nature).
Sri Suka continued : Having spoken thus and bowed low to Sri Hari (disguised as a dwarf) and then to Brahma (the creator) along with Lord Siva (the Source of the universe), Bali, who was (now) free (from bondage) and full of delight, got ready to retire to Sutala (the third region below the earth), accompanied by the (other) demons (too). Having thus restored (the kingdom of) heaven to Indra and fulfilled the desire of Aditi (lndra's mother as well as His own), the Lord ruled over the (whole) universe (as a younger brother and protector of Indra). Seeing his grandson, Bali, who maintained the thread of his line, free from all bondage and a recipient of the Lord's grace, Prahrada, who was steeped in Devotion, spoke (to the Lord) as follows.
Prahrada submitted : To think that You, whose feet are adored even by those (Brahma, Siva and others) that deserve the adoration of the universe, should play the governor  of a fort to us demons I Neither Brahma (the creator) nor Sri (Your divine Spouse) nor (even) Lord Siva (the Destroyer of the universe) has (ever) won such (unique) grace; how, then, could those others (Indra and so on) do so? (It is) by virtue of (their) addiction to the honey of Your lotus-feet (that guardians of the various worlds such as) Brahma and others enjoy opulence and powers (of various kinds), O Lord affording shelter to all I (Such being the case,) we are at a loss to understand wherefore we, those born of a wicked race and following evil ways should have been made the recipients of Your gracious look (kindness). Oh, in Your case-who have released the (different) worlds through the sportful activity of Your inconceivable creative energy, are omniscient, nay, the (very) Self of all and (therefore) regard all with the same eye-a discriminating disposition, in the sense that You are fond of Your devotees (alone), is a wonderful gesture. (But) You (only) exhibit (thereby) the essential characteristic of a wish-yielding tree (which fulfils the desire of only those who betake themselves to it and cannot therefore be justly accused of partiality).
The glorious Lord replied : Prahrada dear, may all be well with you I Depart to (the subterranean region of) Sutala and, rejoicing (there) with your grandson (Bali), bring delight to your kinsfolk. You will always behold Me stationed there, mace in hand; (and) you will have your ignorance (the root of all Karma) wiped out by the infinite joy induced by My sight. Sri Suka went on : Accepting the Lord's command in the word 'A men, and bowing down to Him with joined palms, O Pariksit, Prahrada of sinless mind, the generalissimo of all the Asura forces, walked round the most ancient Person (as a mark of reverence) and, permitted by Him, withdrew to the subterranean world along with Bali. Thereupon Lord Visnu (who takes away the sins of His devotees and) who has His abode in water, O king, spoke (as follows) to the sage Usana (Sukracarya, the preceptor of Bali), sitting near at hand in the midst of (other) priests in the assembly of seers (exponents of the Veda):- "O (holy) Brahmana, (please) accomplish whatever has been left incomplete by your disciple while performing the ritual (sacrifice). (For) whatever is found lacking in rituals is made up (even) when noticed by a Brahmana (and much more when it is actually completed by a Brahmana).