Sunan an-Nasai Book 1, Hadith 312

أَخْبَرَنَا مُحَمَّدُ بْنُ بَشَّارٍ، قَالَ حَدَّثَنَا مُحَمَّدٌ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ سَلَمَةَ، عَنْ ذَرٍّ، عَنِ ابْنِ عَبْدِ الرَّحْمَنِ بْنِ أَبْزَى، عَنْ أَبِيهِ، أَنَّ رَجُلاً، أَتَى عُمَرَ فَقَالَ إِنِّي أَجْنَبْتُ فَلَمْ أَجِدِ الْمَاءَ ‏.‏ قَالَ عُمَرُ لاَ تُصَلِّ ‏.‏ فَقَالَ عَمَّارُ بْنُ يَاسِرٍ يَا أَمِيرَ الْمُؤْمِنِينَ أَمَا تَذْكُرُ إِذْ أَنَا وَأَنْتَ فِي سَرِيَّةٍ فَأَجْنَبْنَا فَلَمْ نَجِدِ الْمَاءَ فَأَمَّا أَنْتَ فَلَمْ تُصَلِّ وَأَمَّا أَنَا فَتَمَعَّكْتُ فِي التُّرَابِ فَصَلَّيْتُ فَأَتَيْنَا النَّبِيَّ صلى الله عليه وسلم فَذَكَرْنَا ذَلِكَ لَهُ فَقَالَ ‏ "‏ إِنَّمَا كَانَ يَكْفِيكَ ‏"‏ ‏.‏ فَضَرَبَ النَّبِيُّ صلى الله عليه وسلم يَدَيْهِ إِلَى الأَرْضِ ثُمَّ نَفَخَ فِيهِمَا ثُمَّ مَسَحَ بِهِمَا وَجْهَهُ وَكَفَّيْهِ - وَسَلَمَةُ شَكَّ لاَ يَدْرِي فِيهِ الْمِرْفَقَيْنِ أَوْ إِلَى الْكَفَّيْنِ - فَقَالَ عُمَرُ نُوَلِّيكَ مَا تَوَلَّيْتَ ‏.‏

It was narrated from Ibn 'Abdur-Rahman bin Abza from his father that a man came to 'Umar and said:"I have become Junub and I do not have any water." 'Umar said: "Do not pray." But 'Ammar bin Yasir said: "O Commander of the Believers! Don't you remember when you and I were on a campaign and we became Junub and could not find water? You did not pray, but I rolled in the dust and prayed. Then we came to the Prophet (ﷺ) and told him about that, and he said: 'It would have been sufficient for you (to do this),' then the Prophet (ﷺ) struck his hands on the ground and blew on them, then wiped his face and hands with them'" - (one of the narrators) Salamah was uncertain and did not know whether that was up to the elbows or just hands. And 'Umar said: "We will let you bear the burden of what you took upon yourself