Nrisimha-chaturdasi is the divine appearance day of Nrisimhadeva, Lord Krishna’s man-lion incarnation, who removes all obstacles on the path of devotional service out of His great compassion.
Srila Prabhupada writes (Bhagavatam 7.8.51, purport):
The Supreme Personality of Godhead in His transcendental form of Lord Nrisimhadeva is always ready to kill the demons who always create disturbances in the minds of honest devotees. To spread the Krishna consciousness movement, devotees have to face many dangers and impediments all over the world, but a faithful servant who preaches with great devotion to the Lord must know that Lord Nrisimhadeva is always his protector.
At Mayapur, Nrisimha-chaturdasi is very special as devotees assemble in great numbers and with great joy to observe this festival and chant the glories of Lord Nrisimhadeva. The Srimad-Bhagavatam class focuses on various aspects of Lord Nrisimhadeva’s pastimes, usually given by two or three devotees.
At dusk a maha-abhisheka is performed to our Deity, technically called Sthanu-Nrisimha because of His standing pose, with sandalwood oil and other precious oils. Since the Deity has performed unbelievable miracles in the lives of several devotees, there is naturally great enthusiasm amongst the devotees. Nrisimhadeva is offered a new dress too. After the arati, anukalpa-prasada [i.e. prasada as on ekadasi] is honored by the devotees.
Srila Bhaktivinoda Thakura, in his Navadvipa-bhava-taranga, writes of the significance that worship of Lord Nrisimhadeva has for a Gaudiya Vaishnava:
Therefore, I pray to the feet of Lord Nrisimhadeva to purify my heart and give me the desire to serve Krishna. Weeping, I beg at the lotus feet of Nrisimha that I may worship Sri Sri Radha and Krishna at Navadvipa-dhama, free from all obstacles.
The devotees aspire for such perfection under the shelter of Sri Nrisimhadeva.