Sunan an-Nasa'i 321
It was narrated that Abu Raja' said:
"I heard 'Imran bin Husain (say) that the Prophet (ﷺ) saw a man who was by himself and did not pray with the people. He said: 'O So and so, what kept you from praying with the people?' He said: 'O Messenger of Allah, I have become Junub and there is no water.' He said: 'You should use earth for that will suffice you.'"
أَخْبَرَنَا سُوَيْدُ بْنُ نَصْرٍ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ، عَنْ عَوْفٍ، عَنْ أَبِي رَجَاءٍ، قَالَ سَمِعْتُ عِمْرَانَ بْنَ حُصَيْنٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم رَأَى رَجُلاً مُعْتَزِلاً لَمْ يُصَلِّ مَعَ الْقَوْمِ فَقَالَ ‏"‏ يَا فُلاَنُ مَا مَنَعَكَ أَنْ تُصَلِّيَ مَعَ الْقَوْمِ ‏"‏ ‏.‏ فَقَالَ يَا رَسُولَ اللَّهِ أَصَابَتْنِي جَنَابَةٌ وَلاَ مَاءَ ‏.‏ قَالَ ‏"‏ عَلَيْكَ بِالصَّعِيدِ فَإِنَّهُ يَكْفِيكَ ‏"‏ ‏.‏