He was among the delegation. He said, "We set out and came to the Messenger of Allah ﷺ. We pledged allegiance to him and prayed behind him. Out of the corner of his eye, he noticed a man who was not keeping his back straight in the bowing and prostration. When the Prophet ﷺ finished the prayer, he said, 'Muslims, there is no prayer for one who does not keep his back straight in the bowing and prostration.'"
حدثنا أبو بكر بن أبي شيبة حدثنا ملازم بن عمرو عن عبد الله بن بدر أخبرني عبد الرحمن بن علي بن شيبان
وكان من الوفد قال خرجنا حتى قدمنا على رسول الله ﷺ فبايعناه وصلينا خلفه فلمح بمؤخر عينه رجلا لا يقيم صلاته يعني صلبه في الركوع والسجود فلما قضى النبي ﷺ الصلاة قال يا معشر المسلمين لا صلاة لمن لا يقيم صلبه في الركوع والسجود