It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that he said: "I prayed behind the Messenger of Allah (peace and blessings be upon him), Sayyiduna Abu Bakr and Sayyiduna Umar (may Allah be pleased with them both), and all of them used to raise their hands when they began the prayer, when they said the takbir for ruku', and when they raised their heads (from ruku') and said the takbir for prostration."
No one narrated this hadith from Abd al-Rahman bin al-Aswad (may Allah have mercy on him) except Layth bin Abi Sulaym (may Allah have mercy on him), and Ibrahim bin Muhammad al-Aslami (may Allah have mercy on him) is alone in narrating it.
Hadith Referenceالمعجم الأوسط / باب الميم / 6464
Hadith Gradingمحدثین:إسناده ضعيف لضعف إبراهيم بن محمد الأسلمي
Hadith Takhrij«قال الطبراني: لم يروه عن عبد الرحمن إلا ليث تفرد به إبراهيم بن محمد الأسلمي «الإعلام بسنته عليه الصلاة والسلام بشرح سنن ابن ماجه الإمام، ج 5، ص 279»» «قال الهيثمي: فيه إبراهيم بن محمد الأسلمي وهو ضعيف «مجمع الزوائد ومنبع الفوائد، ج 2، ص 102»»