Thabit (may Allah have mercy on him) said that Sayyiduna Anas (may Allah be pleased with him) said: I lead you in prayer just as the Messenger of Allah (peace and blessings be upon him) used to lead us in prayer, without any kind of shortfall or addition. Thabit (may Allah have mercy on him) said: Anas (may Allah be pleased with him) used to do something in prayer that I do not see you doing: when he raised his head from bowing, he would stand for so long that one would think he had perhaps forgotten, and when he sat between the two prostrations, he would remain seated for so long that one would think he had perhaps forgotten.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2744