"This current month of October/November is known as “Karttik” in honor of its presiding Deity, Karttik Devi. This is another name for the Daughter of Kirtida, the pleasure potency of Krishna and the ultimate reservoir for all love and devotion. Thus the month of Karttik is especially dear to devotees.
As much as devotees hold this month of Karttik most dear, Karttik Devi loves Her devotees all the more. With the affection of a mother, She considers even the most insignificant service performed during Her month to be of great importance.
Sri Radhika is the presiding Deity of the Karttik vrata and She offers enriched blessings and causeless mercy to the devotees. Any vrata performed during the month of Karttik, even the smallest one, bears the most significant fruit. Moreover, the effects of performing Karttik vrata endure for 100 lifetimes whereas the effects of ordinary vratas last only one lifetime.
What is the nature of Sri Radhika’s mercy? As Srila Prabhupada explained, when one attracts the favor of Srimati Radharani, She personally approaches Krishna and beseeches Him, “Please accept this devotee. This person is better than Me.”
Hearing these words from His most Beloved, Krishna cannot refuse. Thus Krishna’s blessings and causeless mercy follow those of Radha, just as His month follows Hers. In Bhagavad Gita 10.35, Lord Krishna says, “Of months I am November and December . . .”
The month of Karttik is also known as the month of Damodara. Lord Damodara is especially pleased when one offers a ghee lamp during the month of Karttik Devi. Yet Sri Krishna is even more pleased by one who, in the mood of servant of the servant, lights a ghee lamp for someone else to offer to His Beloved.
What is the nature of the blessings of Radha and Krishna? Those blessings provide the impetus to gratefully accept the role of servant of the servant of Their servants, to find his or her place within the disciplic succession, to achieve prayojana, and ultimately to constantly chant the Holy Names within the sacred Hare Krishna maha-mantra."