Dev Diwali
What it is
Dev Diwali arrives on Kartik sud Poonam, the full moon that crowns the sacred month of Kartik, fifteen days after Diwali. Its name means the Diwali of the devas: tradition holds that on this poonam the gods themselves celebrate the festival of light, remembering Bhagwan Shiv's victory over the demon Tripurasura — which is why the day is also called Tripurari Poonam. On the ghats of Kashi, countless lamps are set afloat and the riverbanks blaze; across the country the evening is kept with deepdaan, the offering of lamps, which on this day is said to carry a thousandfold merit.
The poonam also completes the holy month itself. Kartik snan — the month-long discipline of early bathing, tulsi seva and a lamp offered each evening, kept in love of Prabhu — concludes today, and the Tulsi Vivah season closes with the full moon. For Vaishnavs the day is one of quiet fullness rather than fireworks: the year's most sacred month ends under a complete moon, with lamps lit before Thakorji and gratitude for a month spent close to Him.
Why we observe it
If Diwali is the festival of our lamps, Dev Diwali whispers something humbling: even the devas light lamps. Even those who dwell in the heavens long to celebrate, to serve, to bow. For a Vaishnav this is not a distant story but a daily truth of Pushtimarg — before Prabhu there is no rank; gods and jivs alike find their joy only at His charan.
The month of Kartik has trained the heart for exactly this. A month of rising early, of tulsi seva, of a small flame offered each evening — none of it grand, all of it love — and now, on the poonam, the moon itself seems to stand as the completed lamp of the month's bhakti. The deep the Vaishnav lights tonight carries the whole of Kartik within it.
There is a gentle teaching about light here too. Diwali's lamps dispelled the outer darkness of Amas; Dev Diwali's lamps burn under a full moon, where no darkness remains — because true deepdaan was never about darkness at all. It is love, offered simply because the Lord is worthy of it. With that bhav the Vaishnav closes Kartik: lamp lit, kirtan sung, heart full.