Hakam (may Allah have mercy on him) says: I saw Tawus raising his hands at the beginning of the prayer, when going into bowing (ruku‘), and when rising from bowing. One of his students told me that he narrates this from Sayyiduna Ibn ‘Umar (may Allah be pleased with them both), who attributes it to the Prophet (peace and blessings be upon him).
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 5033
Hadith Gradingحکم دارالسلام:حديث صحيح، وهذا إسناد ضعيف لإبهام الرجل من أصحاب طاووس الذى حدث عنه الحكم بن عتيبة.