It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that he said: I saw the Messenger of Allah (peace and blessings be upon him) raising his hands in the prayer. It has also been said about this narration that he did this (raising the hands) before the takbir.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2319