Sahih al-Bukhari, Hadith 821 ⓘ
Narrated 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.
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.
also referenced under: Book 10, Hadith 215 (In-Book) & Volume 1, Book 12, Hadith 784 (USC-MSA)