Mishkat al-Masabih 18 The Offices of Commander and Qadi كتاب الإمارة والقضاء 19

وَعَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسلم: «من بَايَعَ إِمَامًا فَأَعْطَاهُ صَفْقَةَ يَدِهِ وَثَمَرَةَ قَلْبِهِ فَلْيُطِعْهُ إِنِ اسْتَطَاعَ فَإِنْ جَاءَ آخَرُ يُنَازِعُهُ فاضربوا عنق الآخر» . رَوَاهُ مُسلم

‘Abdallah b. ‘Amr reported God’s Messenger as saying, “If anyone swears allegiance to an imam , giving him his hand in ratification and sincere agreement in his heart, he must obey him if he can. Then if another comes and contends with him, cut off that other one’s head.” Muslim transmitted it.