Narrated Al-A`mash:

Shaqiq said, "While I was sitting with `Abdullah and Abu Musa Al-Ash`ari, the latter asked the former, 'If a person becomes Junub and does not find water for one month, can he perform Tayammum and offer his prayer?' (He applied in the negative). Abu Musa said, 'What do you say about this verse from Sura "Al-Ma'ida": When you do not find water then perform Tayammum with clean earth? `Abdullah replied, 'If we allowed it then they would probably perform Tayammum with clean earth even if water were available but cold.' I said to Shaqiq, 'You then disliked to perform Tayammum because of this?' Shaqiq said, 'Yes.' (Shaqiq added), "Abu Musa said, 'Haven't you heard the statement of `Ammar to `Umar? He said: I was sent out by Allah's Messenger (ﷺ) for some job and I became Junub and could not find water so I rolled myself over the dust (clean earth) like an animal does, and when I told the Prophet (ﷺ) of that he said, 'Like this would have been sufficient.' The Prophet (ﷺ) (saying so) lightly stroked the earth with his hand once and blew it off, then passed his (left) hand over the back of his right hand or his (right) hand over the back of his left hand and then passed them over his face.' So `Abdullah said to Abu- Musa, 'Don't you know that `Umar was not satisfied with `Ammar's statement?' " Narrated Shaqiq: While I was with `Abdullah and Abu Musa, the latter said to the former, "Haven't you heard the statement of `Ammar to `Umar? He said, "Allah's Messenger (ﷺ) sent you and me out and I became Junub and rolled myself in the dust (clean earth) (for Tayammum). When we came to Allah's Apostle I told him about it and he said, 'This would have been sufficient,' passing his hands over his face and the backs of his hands once only.' "

Narrated Aisha:

A necklace of mine was lost at Al-Baida' and we were on our way to Medina. The Prophet (ﷺ) made his camel kneel down and dismounted and laid his head on my lap and slept. Abu Bakr came to me and hit me violently on the chest and said, "You have detained the people because of a necklace." I kept as motionless as a dead person because of the position of Allah's Messenger (ﷺ) ; (on my lap) although Abu Bakr had hurt me (with the slap). Then the Prophet (ﷺ) woke up and it was the time for the morning (prayer). Water was sought, but in vain; so the following Verse was revealed:-- "O you who believe! When you intend to offer prayer.." (5.6) Usaid bin Hudair said, "Allah has blessed the people for your sake, O the family of Abu Bakr. You are but a blessing for them."

Shaqiq reported: I was sitting in the company of Abdullah and Abu Musa when Abu Musa said: 0 'Abd al-Rahman (kunya of 'Abdullah b. Mas'ud), what would you like a man to do about the prayer if he experiences a seminal emission or has sexual intercourse but does not find water for a month? 'Abdullah said: He should not perform tayammum even if he does not find water for a month. 'Abdullah said: Then what about the verse in Sura Ma'ida:" If you do not find water, betake yourself to clean dust"? 'Abdullah said: If they were granted concession on the basis of this verse, there is a possibility that they would perform tayammum with dust on finding water very cold for themselves. Abu Musa said to Abdullah: You have not heard the words of 'Ammar: The Messenger of Allah (ﷺ) sent me on an errand and I had a seminal emission, but could find no water, and rolled myself in dust just as a beast rolls itself. I came to the Messenger of Allah (ﷺ) then and made a mention of that to him and he (the Holy Prophet) said: It would have been enough for you to do thus. Then he struck the ground with his hands once and wiped his right hand with the help of his left hand and the exterior of his palms and his face. 'Abdullah said: Didn't you see that Umar was not fully satisfied with the words of 'Ammar only?