Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates: When the Prophet (peace and blessings be upon him) went into ruku' (bowing), if a cup of water had been placed on him, it would have stayed in place; the reason for this was that he kept (his back) perfectly level.
Imam al-Tabarani recorded this narration in al-Mu'jam al-Saghir. Its chain contains a narrator, Muhammad bin Thabit, and he is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2740
Hadith Gradingمحدثین:إسنادہ ضعیف
Hadith Takhrij«أخرجه المعجم الصغير للطبراني برقم: 35»