Sahih Bukhari Volume 1, Book 10, Hadith 670

حَدَّثَنَا آدَمُ، قَالَ حَدَّثَنَا شُعْبَةُ، قَالَ حَدَّثَنَا أَنَسُ بْنُ سِيرِينَ، قَالَ سَمِعْتُ أَنَسًا، يَقُولُ قَالَ رَجُلٌ مِنَ الأَنْصَارِ إِنِّي لاَ أَسْتَطِيعُ الصَّلاَةَ مَعَكَ‏.‏ وَكَانَ رَجُلاً ضَخْمًا، فَصَنَعَ لِلنَّبِيِّ صلى الله عليه وسلم طَعَامًا فَدَعَاهُ إِلَى مَنْزِلِهِ، فَبَسَطَ لَهُ حَصِيرًا وَنَضَحَ طَرَفَ الْحَصِيرِ، صَلَّى عَلَيْهِ رَكْعَتَيْنِ‏.‏ فَقَالَ رَجُلٌ مِنْ آلِ الْجَارُودِ لأَنَسٍ أَكَانَ النَّبِيُّ صلى الله عليه وسلم يُصَلِّي الضُّحَى قَالَ مَا رَأَيْتُهُ صَلاَّهَا إِلاَّ يَوْمَئِذٍ‏

Narrated By Anas bin Sirin : I heard Anas saying, "A man from Ansar said to the Prophet, 'I cannot pray with you (in congregation).' He was a very fat man and he prepared a meal for the Prophet and invited him to his house. He spread out a mat for the Prophet, and washed one of its sides with water, and the Prophet prayed two Rakat on it." A man from the family of Al-Jaruid asked, "Did the Prophet used to pray the Duha (forenoon) prayer?" Anas said, "I did not see him praying the Duha prayer except on that day."