Abdur Rahman bin Ali bin Shaiban narrates from his father, who was included in the delegation. He says: We presented ourselves before the Prophet Muhammad (peace be upon him). We performed prayer behind the Prophet Muhammad (peace be upon him). When the Prophet Muhammad (peace be upon him) completed the prayer, a man was standing alone and performing prayer. The Prophet Muhammad (peace be upon him) stopped by him. When that man completed his prayer, the Prophet Muhammad (peace be upon him) said to him: Perform your prayer again, for the prayer of a person who stands alone behind the row is not valid.
Hadith Referenceصحیح ابن حبان / كتاب الصلاة / 2202
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «الإرواء» (2/ 328 و 329).فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح، رجاله ثقات كما قال البوصيري في «مصباح الزجاجة» ورقة 19.