Sahih al-Bukhari 860
Narrated Anas bin Malik:
My grandmother Mulaika invited Allah's Messenger (ﷺ) for a meal which she had prepared specially for him. 
He ate some of it and said, "Get up. I shall lead you in the prayer." I brought a mat that had become 
black owing to excessive use and I sprinkled water on it. Allah's Messenger (ﷺ) stood on it and prayed two 
rak`at; and the orphan was with me (in the first row), and the old lady stood behind us.
حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنِي مَالِكٌ، عَنْ إِسْحَاقَ بْنِ عَبْدِ اللَّهِ بْنِ أَبِي طَلْحَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، أَنَّ جَدَّتَهُ، مُلَيْكَةَ دَعَتْ رَسُولَ اللَّهِ صلى الله عليه وسلم لِطَعَامٍ صَنَعَتْهُ، فَأَكَلَ مِنْهُ فَقَالَ ‏
"‏ قُومُوا فَلأُصَلِّيَ بِكُمْ ‏"‏‏.‏ فَقُمْتُ إِلَى حَصِيرٍ لَنَا قَدِ اسْوَدَّ مِنْ طُولِ مَا لُبِسَ، فَنَضَحْتُهُ بِمَاءٍ فَقَامَ رَسُولُ اللَّهِ صلى الله عليه وسلم وَالْيَتِيمُ مَعِي، وَالْعَجُوزُ مِنْ وَرَائِنَا، فَصَلَّى بِنَا رَكْعَتَيْنِ‏.‏