بِسْمِ اللَّـهِ الرَّحْمَـٰنِ الرَّحِيم
Some people think that prostrating on the ground while praying, or on martyrs' tombs is a sign of worshipping the ground or of the martyrs, and is therefore a kind of polytheism.
In answer the above question, it should be noted that there is an undisputable difference between "prostration for God "alsujudu lillahi" and "prostration on the ground "alsujudu 'ala al-ard" The above objection has been raised because the distinction between the two phrases has not been made out. The former definitely means, "Prostration is done exclusively for God", but the latter means "prostration on the ground." In other words, when we prostrate on the ground, we do so exclusively for God. Muslims all over the world prostrate on something for God and so do all pilgrims to the sacred House (the Ka'bah) who prostrate on the stone of the sacred House for Allah.
It is thus clear that prostration on the earth, on the plants and on similar objects never denotes worshipping them; rather it is a prostration dedicated to God, manifested in utmost humbleness, as low as the earth. It is also clear that prostration on turbah differs from prostration for turbah. The holy Qur'an say, "And onto Allah falleth prostrate whosoever is in the heavens and the earth. 13:15." Also, the holy Prophet said, "For me has he earth been made a place of worship and pure."  Thus, "prostrating for God" and" prostrating on the earth, Turbah, are not the least in opposition. They are harmonious because to prostrate on the earth and on the plant signifies the utmost humbleness before One God.
Now, to further elucidate the Shiites' view, the following citation, words of Imam Sadiq, the six Imam, peace be upon him, is worth mentioning:' "Husham ibn al-Hakam says, 'I asked Imam Sadiq (a.s) about what prostration is permissible on and what is not.' The Imam responded: ' It is not permissible to prostrate on anything except on the ground or on what grows from it unless these products are used as food or for dress..." I said ' May I be your sacrifice! What is the rationale behind it?' The Imam answered, 'Prostration means being humble and obedient exclusively towards God, and it is not proper to prostrate upon what could be eaten or used as cloth. Moreover, those whose hearts are filled with the love of the world are the slaves of food and dress. As man is in a state of worshipping God while he is in prostration, it is not worthy for him to put his forehead upon what is an object of worship for those stubborn worshippers of material things who bow in respect before the material representations. Prostration on the earth is, thus, preferable since it is in greater harmony with the state of humbleness towards God."
These words are a clear proof to the fact that prostrating on the earth is done exclusively because it is more in harmony with being humble before God, the Exalted.
The next question asks why Shiites prostrate on the earth and on some plants, but not on all things. The answer is that just as an act of worship must be legalized by Islam, so should the manner and details of performing the act be taken from the words and deeds of its law-maker, the holy Prophet (a.s), who is in the language of the Qur'an, an excellent exemplar for all the pious.
Below are some canonical Islamic traditions which describe the Prophet's Sunnah and which indicate that the Prophet, (a.s) used to prostrate on the earth as well as on what grows from the earth, such as straw mat; this is exactly in the same manner as the Shiites believe in:
1) A group of Muslim traditionists have, in their sihah and masanid, quoted the Prophet as having said "For me has the earth been made a place of worship and pure."
The word "Ja'al" (to make) has a legislative connotation making it clear that it is a divine command issued to the followers of Islam, thus proving it to be lawful to prostrate on the earth, stone and other particles which constitute the earth's crust.
2) Other traditions specify that the Noble Prophet used to order Muslims to put their foreheads on the ground while in prostration. Umm Salamah, the Prophet's wife, has quoted the Prophet as having said: "tarrib wajhaka lillah" – "put your face on the dust for the sake of Allah." The word Tarrib comes from the word turab, meaning dust.
There are two implications in the word "Tarrib" used by the Prophet: first, one should put his forehead on "Turab", the dust, and second it is an order which must be carried out, since the word "Tarrib" is a derived from "turab", meaning dust, and is used an imperatively.
3) The Noble Prophet's deeds are clear proofs and bright lights showing the way to the Muslims. Wa'il ibn Hajar says, "Whenever he was in prostration, the Prophet (a.s) put his forehead and nose on the ground." Anas ibn Malik, Ibn-'Abbas, some the Prophet's wives such as 'a'ishah and Umm Salamah, as well as many of the narrators of the Prophetic traditions have narrated the following: "The Prophet, (a.s), used to prostrate on khumrah, (a mat made from palm fibers)." Also, Abu-Sa'id, a companion of the Prophet says, "I went to the Prophet (a.s), and saw him performing prayers on a straw mat." This is further clear evidence in support of the Shiites' view who maintain that it is permissible to prostrate on what grows from the ground, provided that it is not used as food, and that it could not be used as some kind of dress material.
4) The words and deeds of the companions of the Prophet and those of the second generation of the narrators of traditions, tabi'un, are also clear indications to the Noble Prophet's Sunnah. Jabir ibn 'Abdullah Ansari says, "I used to perform the noon prayers together with the holy Prophet (a.s). I would take a handful of pebbles to keep them in my hand to allow the pebbles to get cool; I put my forehead on them. This was because the weather was very warm" The narrator (of the tradition) then adds, "Prostration on the dress he had on, if permitted, would have been easier than taking and keeping the pebbles."
Ibn Sa'd (d. 209 A.H.) says, in his al-Tabaqat al-Kubra, "Masruq ibn al-Ajda' used to take a piece of clay brick along to prostrate on whenever he made a sea voyage." Masruq ibn al-Ajda' was a member of the tabi'un group, who was also an associate of Ibn Mas'ud, whom Ibn Sa'd considers among the first generation of narrators after the companions of the Prophet, and the one who has directly quoted traditions from Abu-Bakr, 'Umar, 'Uthman, 'Ali (a.s) and 'Abdullah ibn Mas'ud.
This lucid statement is a proof against the baseless expressions of those who claim it to be polytheism and an innovation in religion if one carries along a piece of the turbah clay. Also, it discloses the fact that the vanguard in the history of Islam themselves used to do the same. For example, Nafi' says, "'Abdullah ibn 'Umar used to take his turban off to bare his forehead when he wanted to prostrate." Razin says, "'Ali ibn 'Abdullah, son of 'Abbas, wrote and said, 'Send me a piece of stone from al-Marwah mountain so I will prostrate on it."
5). Muslim transmitters of hadiths have also narrated cases when the holy Prophet prohibited men from putting a part of their turban on their foreheads when they ware prostrating. Salih al-Saba'i says, "Once the holy Prophet saw that a man who was in prostration had covered his forehead with his turban. The Prophet (a.s) bared the man's forehead."
'Ayyad ibn 'Abdullah of the Quraysh says, "The holy Prophet (a.s) saw that a man had prostrated on a part of his turban. Pointing to the man's forehead, the Prophet told him to take it off."
It is clearly understood from these traditions that prostrating on the ground was an uncategorical necessity at the time of the holy Prophet so much so that if a Muslim put a part of his turban on the ground to prostrate on, the Messenger of God would prohibit him from doing so.
6) The Shiites infallible leaders, who are according to the Hadith Thaqalayn, peers of, and inseparable from the Quran, and are also the household of the Prophet, have clearly expressed this fact: Imam Sadiq (a.s) says, "Prostrating on the ground is an obligatory duty, and on straw floor covering, the khumrah, is a Sunnah." Elsewhere he says, "It is not permissible to prostrate on anything except on the ground or on what grows from it, unless these products are used as food or for dress.
All the proofs stated above are clear evidence to the fact that not only the traditions quoted from the household of the Prophet, but also the Sunnah of the Messenger of God, and the deeds of his companions, and of the first generation of the narrators after the companion, all emphasize the necessity of prostrating on the ground and on what grows from it unless these products are used for food or for dress. Also, there is no doubt that it is permissible to prostrate on the things that have been specified, whereas there is doubt and uncertainty as to whether it is permissible to prostrate on other things. Therefore, to observe prudence that leads to salvation, it is befitting to prostrate only on the things that have been mentioned.
In conclusion, it should be reminded that the question raised here is a juridical issue; lots of differences of opinion can be seen among Muslim jurists concerning similar subsidiary questions which should, however, not be a cause for anxiety since similar juridical differences also abound the four Sunni Schools. As an example, the Malikiyyah say that it is a recommended deed to put one's nose on the ground when one is in prostration while the Hanbaliyyah consider it an obligatory duty and say that such an action nullifies the prayer if it is not observed.
 Sahih al-Bukhari, The Book of Prayers, al-Salat, p. 91.
 Bihar al-Anwar, vol. 85, p. 147 quoting 'Ilal al-Shara'i'.
 Sunan al-Bayhaqi, vol. 1, p. 212, the chapter on "Having recourse to wholesome dust"; Sahih al-Bukhari, the book of prayers, p. 91; also Ibn Taymiyah's Iqtida' al-Sirat al-Mustaqim, p. 332.
 Kanz al-'Ummal, vol. 7 printed in Damascus, p. 465, tradition no. 19809, The Book of Prayers and Prostration and what belongs to it.
 Ahkam al-Qur'an, vol. 3, p. 209, printed in Beirut, the chapter on Prostration.
 Sunan al-Bayhaqi, vol. 2 p. 421, The Book of performing Prayers, on Khumrah (clay).
 Sunan al-Bayhaqi, vol. 2 p. 421. The Book of performing prayers on Hasir.
 Sunan al-Bayhaqi, vol. 1 p. 439. The Book of al-Salat, the chapter on 'What has been narrated concerning how to perform the prayers quickly when the weather is warm.'
 Al-Tabaqat al-Kubra, vol. 6, p.79, printed in Beirut on the biography of Masruq ibn al-'Ajwa'.
 For further information, refer to the book Siratuna by 'Allamah al-Amini.
 Sunan al-Bayhaqi, vol. 2 p. 105; the book of al-Salat; Bab al-Kashf 'an al-Sajdah fi al-Sojud.
 Al-Azraqi, Akhbar Makkah, vol. 3, p. 151.
 Sunan al-Bayhaqi, vol. 2, p. 105.
 Sunan al-Bayhaqi, vol. 2, p. 105.
 Wasa'il al-Shiah, vol. 3, p. 593, The Book of al-Salat, chapter: ma yusjadu 'alayh, tradition No 7.
 Wasa'il al-Shiah, vol. 3, p. 591, The Book of al-Salat, chapter: ma yusjadu 'alayh, tradition No 1.
 Al-Fiqh 'Ala al-Madhahib al-Arba'ah; Vol. 1, p. 161, printed in Egypt; The Book of al-Salat, al-Sujud.
رَبَّنَا تَقَبَّلْ مِنَّا إِنَّكَ أَنتَ السَّمِيعُ الْعَلِيمُ
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