lighting of Candles for Imam Husain (as)

The below narration shows that lighting of candles/lamp upon the martyrdom (Shahadah) of Imam Husain is Mustahab.

عدة من أصحابنا، عن سهل بن زياد، عن عثمان بن عيسى، عن عدة من أصحابنا قال: لما قبض أبوجعفر (عليه السلام) أمر أبوعبدالله (عليه السلام) بالسراج في البيت الذي كان يسكنه حتى قبض أبوعبدالله (عليه السلام) ثم أمر أبوالحسن (عليه السلام) بمثل ذلك في بيت أبي عبدالله (عليه السلام) حتى خرج به إلى العراق ثم لا أدري ما كان

A number of our people have narrated from Sahl ibn Ziyad from Uthman ibn Isa from a number of our people has narrated the
following:

"When Abu Jafar Imam Baqir (as) passed away Abu Abdillah Imam Sadiq (as), commanded to light a lamp in the house where he lived until Abu Abdillah Imam Sadiq (as) passed away. Thereafter Abu al-Hassan Imam Kazim (as) did a similar thing in the house where Abu Abdillah Imam Sadiq (as) lived until he was taken to Iraq and thereafter I do not know what happened."

[Source: al-Kafi, Vol. 3, Pg. 251, Hadith. 5]

* You will see in Karbala many people lighting candles on the night of 11st of Moharram. And this act would be considered Mustahab based on the above narration.