Hazrat Sa’ad bin Obadah RadiyAllahu Anhu narrates that he came to RasoolAllah Sallallahu Alaihi wa Sallam and
enquired, ‘Ya RasoolAllah Sallallahu Alaihi wa Sallam, my mother has passed away. Which charity is best for her?’
RasoolAllah Sallallahu Alaihi wa Sallam replied, ‘Water.’’
Thus Hazrat Sa’ad RadiyAllahu Anhu dug a well for the people and announced that this well is for my mother. (The
reward of this goes to my mother.) [Ashatul Lam’aat]
It is clear from the above narration that the well was for the mother of Sa’ad. This means the reward of the good deed goes to the mother of Sa’ad and the well is attributed to her.
Thus it is clear that any good deed presented to the deceased can be attributed to him. So when we say that this
‘niyaz’ is for Imam Hussain RadiyAllahu Anhu or this food is for Imam Hussain means that the reward goes to Imam
Hussain. This kind of food does not become unlawful in anyway as is a misconception with some minorities as we see
that the water from the well for Hazrat Sa’ad’s mother was drank by the people of Madinah.
Some people also question the general custom of Muslims to make ‘Khichda’ on this day. It is reported the arc of Nooh Alaihis Salaam rested at the Mount of Joody after the mighty flood on the day of Aashura. Hazrat Nooh Alaihis Salaam mixed all the seven type of grains and cereals in a large pot and cooked it, this dish was later called Khichda. Thus it is reported that to make Khichda on this day is a sunnah of Nuh Alaihis Salaam.
Moreover Hazrat Khwaja Nizamuddin Awliya RadiyAllahu Anhu narrates that whosoever mixes Excellence of Muharram & Imam-e-Hussain Radiyallahu Anh seven types of grain on this day will get a reward for each grain and will have a sin forgiven. [Tafseer e Roohul Bayan]