Hadith 422
كان رسول الله صلى الله عليه وسلم يرفع يديه كلما ركع وكلما رفع ثم صار الي افتتاح الصلاة وترك ما سوي ذالك
"Whenever the Messenger of Allah (peace and blessings be upon him) would go into bowing (ruku') and rise from bowing, he would raise his hands. Then, he would raise his hands only at the beginning of the prayer and not at any other time."
