Sahih Bukhari Volume 1, Book 10, Hadith 822

حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، قَالَ حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ، عَنْ ثَابِتٍ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ إِنِّي لاَ آلُو أَنْ أُصَلِّيَ بِكُمْ كَمَا رَأَيْتُ النَّبِيَّ صلى الله عليه وسلم يُصَلِّي بِنَا‏.‏ قَالَ ثَابِتٌ كَانَ أَنَسٌ يَصْنَعُ شَيْئًا لَمْ أَرَكُمْ تَصْنَعُونَهُ، كَانَ إِذَا رَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ قَامَ حَتَّى يَقُولَ الْقَائِلُ قَدْ نَسِيَ‏.‏ وَبَيْنَ السَّجْدَتَيْنِ حَتَّى يَقُولَ الْقَائِلُ قَدْ نَسِيَ

Narrated By Thabit : Anas said, "I will leave no stone unturned in making you offer the prayer as I have seen the Prophet making us offer it." Anas used to do a thing which I have not seen you doing. He used to stand after the bowing for such a long time that one would think that he had forgotten (the prostrations) and he used to sit in-between the prostrations so long that one would think that he had forgotten the second prostration.