Hello muslim720,
as per reference from asktheshiekh.com, we have this question and exerpt :
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1. TheEarth is a Place of Prostration
There is a narration narrated in Sahih Muslim and Sahih Bukhari, as well as the Shia books, where the Prophet (pbuh) says:
“The earth is made for me as place of prostration and purification.”
(Bukhari1:209, Muslim 1:371, Wasa’elu-Shi’a 3:423)
From this narration, we understand that when we prostrate, it should be on ‘earth’ or something directly from the earth. This includes soil, sand, pebbles and minerals (except gold and silver). It also includes paper and leaves from trees because they grow from the earth. (Tissue is probably the last option if nothing else is available).
The other condition is that the thing we pray on must not be wearable or edible. Therefore, we cannot pray on leaves from plants which are edible or from which clothes can be made (e.g. cotton).
Imam al-Sadiq (as) says:
“Prostration is only allowed on earth or things that are from the earth, except those things which can be worn or consumed”. (Wasailul Shia, 3:591)
2. Why we do not pray on Carpet?
We do not pray on carpet because it is not earth and is not made from earth. The above narration says that we should pray on the earth, and therefore carpet is no something we can pray on. This is confirmed by other narrations. Abu Said al-Khudri narrates about the Prophet:
“We were in the mosque and the roof of the mosque was made of date palm branches so that we could not see up into the sky. One day it rained heavily. The Prophet (pbuh) led the prayer with us, so much so that I saw the marks of the mud on the forehead of the Prophet (pbuh…” (Bukhari, 2:386)
A’isha narrates:
“The Prophet (pbuh) never placed anything between his forehead and the earth…”
(Mosnad Imam Ahmad, 6:58)
At the time of the Prophet, carpets did exist and if the Prophet (pbuh) wished, he could have prayed on a carpet or laid the mosque’s floor with carpet. However, this never happened.
3. Narrations about the Straw Mat
We also have many narrations from Sunni sources that the Prophet (pbuh) would have a small straw square that he would prostrate on. It seems that when it was too hot to place one’s forehead on the soil, the Prophet would use a straw mat to prostrate on. As this is made from trees, it is considered a product of the earth.
Um Salama: ‘The Prophet would pray on a small strawmat’.
Anas: ‘The Prophet would pray on a straw mat’.
(Bukhari, 1:231)
Therefore, it is at least a precaution to avoid praying on carpet as the Prophet (pbuh) did not ever do this. Imam al-Sadiq (as) says:
“I prefer that he prostrates on the earth. The Messenger of Allah (pbuh) used to like to place his forehead on the earth. I like for you what the Messenger of Allah (pbuh) used to like.”
(WasailulShia)
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This should be able to give you sufficient reason for allowing the prayer on a Turbah and why Shi'ite belief negates the allowing of praying on things like prayer mats, rugs, etc.
As for my own side note, you say
Forget the sajdah to Imams [ra] bit, when they quote our narrations in favor of prostrating on soil, I ask them if they know the points of sajdah. There are 7. One of those 7 points is the face (nose plus forehead). Unless the turbah is by the size of a small plate, the Shias end up touching the turbah with their forehead only. So out of the 7 points of sajdah, they only fulfill 1 (actually half...coz only their foreheads come in contact with the turbah, not nose)!
The remaining six points - palms, kneecaps and toes - come in contact with the prayer rug which, for the most part, is made of cotton. Just like paper is derived from trees, and Shias consider it permissible to prostrate on paper, cotton is grown on trees. So where is the issue?
I am sure you do not seriously consider the nose and the forehead the same point? What is the reasoning behind this? This is the first time I heard a sunni actually say that the touching of the nose is actually PART of the prayer. If we say this, then we would actually have 18 places of contact, rather then only 7; this is if you count the fingers on the hand part of contact? If you do not count the fingers on your hand as separate parts, why do we consider the forehead and nose the same part ?
Narrated Ibn `Abbas: The Prophet(saw) said, “I have been ordered to prostrate on
seven bones i.e. on the forehead along with the tip of the nose and the Prophet pointed towards his nose, both hands, both knees and the toes of both feet and not to gather the clothes or the hair.”(Sahih al-Bukhari #812)
The nose does not have a bone at it's tip? It is cartilage, a part of flesh that can be contorted. It has no contact with bone. Not even that, the lower and middle part of the nose is cartilage as well! See this brother
http://www.mayoclinic.org/diseases-conditions/broken-nose/multimedia/locations-of-the-nasal-bone-and-cartilage/img-20007155I can only assume the part ' tip of the nose and the Prophet pointed towards his nose' in the bukhari narration is inconsistent, as two very prominent sunni madthabs disagree with it as well:
( Ash-Shawkānī said: ‘‘Ulamah differed regarding the obligation of prostrating oneself on the seven bones: Al-’Itratu and Ash-Shāfi‘ī in one of his opinions held that it is an obligation that one prostrates oneself on the seven bones. Abū Hanifah and Ash-Shāfi‘ī later on and other Fuqahā’ held that the obligation is to prostrate oneself on one’s forehead only.) But the only problem is that the only bone in your nose is too high up to touch in prostration. The only possibility with that is if you squished your entire face to the ground, which is very uncomfortable( I tried lol ) and we do not see that happening, even with sunni brothers.