vaisakhasya caturdasyam suklayam sri nrikesari
jatas tad asyam tatpujot-savam kurvita savratam
(Padma Purana)

“Sri Narasimha Deva appeared on the fourteenth lunar day (Chaturdasi-tithi) of the bright fortnight of the month of Vaisakha. So, on this day, it is proper to worship and celebrate the appearance of Narasimha Deva by following the rules of fasting and others.”

prahlad-klesa nasaya ya hi punya caturdas
i pujayet tatra yatnenahareh prahladm agratah
(from the Agamas)

“It is proper to first worship Prahlad before worshipping Narasimha because the holy fourteenth lunar day of the bright fortnight has appeared in order to remove the distress of Prahlad.”

It is written in the Brihan-narasimha Purana as follows: Prahlad Maharaja desired to know from Sri Narasimha Deva how he had developed devotion to His lotus feet.

Narasimha Deva replied, “In ancient times, there lived a Brahmana named Vasu Sharma in the city of Avanti, who was well-versed in the Vedas. His good wife Sushila was famous throughout the three worlds for her virtuous conduct and ideal devotion to her husband. Vasu Sharma fathered five sons in Sushila’s womb. His first four sons were learned persons of good conduct and devoted to their father. But you, the youngest son, became attracted to a prostitute and lost your character. You were then known as Vasudeva. Your virtuous conduct was destroyed in the company of that prostitute. Due to a quarrel with the prostitute, on the Narasimha Chaturdasi Tithi both of you stayed awake throughout the night and unknowingly observed a fast. Therefore, both of you obtained the fruits of observing Narasimha Chaturdasi-vrata.

The prostitute enjoyed as an Apsara in various ways in heaven and then became My favourite. As the son of Hiranyakasipu, you also took birth as My dear devotee. By observing this fast, Brahma has obtained the power of creation and Mahesvara has obtained the power of destruction of the three worlds. Other people also achieve all kinds of power and perform observance of this vow to fulfil all their desired objectives.” In his Laghu-bhagavatamrita, Srila Rupa Gosvami has written about the pre-eminence of the Lord’s appearance as Sri Narasimha Deva, quoting the following reference from Sri Padma Purana:

narasimha-rama-krishneshu sad-gunyam paripuritam
paravasthas tu te tasya dipad utpanna-dipa-vat
(Padma Purana)

“Narasimha, Rama and Krishna possess the pre-eminent presence of the totality of sixty attributes. Just as one lamp lights other lamps and then all lamps follow the same nature, similarly, although Rama and Narasimha are manifested forms from the Prime Supreme Lord Sri Krishna, all three hold the supreme position with sixty attributes.”