TASYAM VISNU TITHAU KECID DHANYAH KALIYUGE JANAH
YE'BHYARCAYANTI DEVESAM JAGRATAH SAMUPOSITAH
(HARI BHAKTI VILASA 15/307 from BRAHMA PURANA Suta Gosvami speaks)
This day (Janmastami day) removes all kinds of sins. Specifically in Kali-yuga, if someone fasts on this day, remains awake overnight and worships Lord Sri Hari properly, those people are worshipable.