It also has to be made clear that Shias believe it is not obligatory to do prostration while putting the forehead on the soil of Karbala. The obligation is to do prostration on the earth or what grows on it that is not used for food -such as fruits and vegetables- or to be worn -such as cotton-. Imam Al-Sadiq (a.s) stated: “Prostration is unlawful except on the ground (earths soil and dirt) or what grows on the earth that is not used as food nor to be worn” and when asked about the reason behind this he (a.s) replied: “Because prostration is obedience (submission) to Allah (swt), so it should not be on food and clothes. Since the worshipers (slaves) of this world are worshipers (slaves) of what they eat and wear, and during prostration this person is worshiping Allah (swt). So they should not put their forehead on what worshiped by the slaves of this world…”(1). Therefore we Shias are following the orders of Ahl Al-Bayt (a.s) to put our foreheads on what they ordered us to put it on during prostration and by that we are obeying Allah (swt).
There are also sayings in Sunni Muslims’ sources that the prophet (pbuh) would practice prostration likewise.
Anas bin Malik stated: “We used to pray with the Prophet in scorching heat, and if someone of us could not put his face on the earth (because of the heat) then he would spread his clothes and prostrate over them.” (2)According to this hadith only in exceptional circumstances the companions of the prophet would prostrate on clothes.
Abu Sa'id al-Khudri stated: “I saw Allah's prophet prostrating in mud and water and saw the mark of mud on his forehead.”(3)
According to al-Shawkani, a famous Sunni scholar, more than ten companions of the Prophet (pbuh) have narrated traditions mentioning his prostration on a Khumrah(4), and he lists all the Sunni sources recording these traditions which include Sahih Muslim, Sahih al-Tirmidhi, Sunan Abu Dawud, Sunan al-Nasa'i and many others(5) such as what was narrated by Maymuna “Allah's prophet would pray on a Khumrah.”(6)
Even though it is permissible to put the forehead on any soil, Shias prefer to use the soil of Karbala because of the sacredness given to it by Ahl Al-Bayt (a.s). Imam Al-Sadiq (a.s) would not do prostration except on the soil of Imam Hussein (a.s)(7) and there are dozens of other sayings about its holiness and its recommendation(8).
Shias for a long time have kept this earth with them. Then, fearing that it might be desecrated, they kneaded it into small tablets or pieces, which are now called Turbah. During prayers we prostrate on it not as a compulsory act but because of its special nature. Otherwise, when we have no pure soil with us, we prostrate on clean earth, or something that originates from it.
It is a pity that some people maliciously insist that Shias worship stones or that they worship Hussein (a.s). The truth is that we worship Allah alone by prostrating on the Turbah, not to it. And we never worship Imam Hussein (a.s), Imam Ali (a.s), or the Prophet Muhammad (pbuh) let alone a piece of soil. We worship only Allah, and it is in accordance with Allah's order that we perform prostration only on pure earth.”(9)
1. ” Wassail Al-Shia v5 p343
2. Al-Bukhari, Sahih (English translation), vol. 2, book 22, no. 299
3. Al-Bukhari, Sahih (English translation), vol. 1, book 12, no. 798; vol. 3, book 33, no. 244
3. "Khumrah is a small mat made from palm fibers or other material…. and it is like that which the Shias use for prostration."
4. [Talkhis al-Sihah, p. 81] and Ibn al-'Athir, another famous Sunni scholar, in his Jami al-'Usul stated "Khumrah is [like that] upon which the Shi'ah of our time perform their prostrations." [Ibn al-'Athir, Jami' al-Usul, (Cairo, 1969), vol. 5, p. 467]
5. Al-Shawkani, Nayl al-Awtar , Chapter of Prostration on the Khumrah, vol. 2, p. 128
6. Al-Bukhari, Sahih (English translation), vol. 1, book 8, no. 378
7. Wassail Al-Shia v5 p366
8. Al-Manaqib, vol. 2, p. 251, Misbah al-Mutahajjad, p. 511,Wassail Al-Shia v5 p265-267
9. We took this part from https://www.al-islam.org/articles/laws-practices-why-do-shiah-prostrate-turbah as it was beautifully put and we changed a little in it.