King Bali after he was pushed down in Patala (which is said to be demon’s colony) had made a request for the last time. And his request was to allow him to visit Kerala every year to make sure that his people not only happy but also contented and had no dearth of food. Lord Vishnu was very happy to grant this boon to Mahabali. Vishnu also granted him the boon that the next Indra, i.e., the eighth King of Devas would be him (Purandara being the current Indra) during Savarni Manu, the eighth Manu’s time.
King Bali offered his salutations to Shiva, Brahma & Vishnu before leaving for Patala.
In short the basis of the story (repeating in the texts theory) is irrespective of Bali or Ravana, all are bestowed with enormous potentialities for both good and bad.
As mentioned by the scholar Veermani P Upadhyaya a sinful person cannot be protected by divinity as well inspite of acting as ‘mahasriman’ or the owner. It is noted that, Bali did not lose his faith on God inspite of Lord Vishnu testing him.
Vamana’s mission got blessed by Ganesha. Few are of the belief that Ganesh blessed Vishnu in Vamana’s avtar.
Ropes tied around Bali
It is said that Bali always sticked to his words when it came to abiding by Vamana’s requests, but at times it is said that he was tied by Varuna’s ropes by Garuda as Vamana was not able to set his foot on earth and so Bali had requested that he should place it on his head. As mentioned in Bhagavata Purana it is mentioned that Bali gets released on Brahma’s directions to Vamana. And hence Bali prostrated before Vishnu after he got freed from ropes. It is stated in the Padma Purana that not only Bali but also his friends, followers & relatives were tied.