Many people accuse the prophet Muhammad (pbuh) of killing many people with his own hands, however, the reality is that it is not reported anywhere that he ever killed anyone with his own hands except what follows in the incident below in self defense during the battle of Uhud.
Ibn Ishaq related that: “When the Messenger of Allah [pbuh] was going up the hillock, he was followed by Ubai bin Khalaf who was saying: ‘Where is Muhammad [pbuh]? Either I kill him or I will be killed.’ The Companions of Muhammad [pbuh] said: ‘O Messenger of Allâh, do you mind if one of us combats with him?’ But the Messenger of Allah [pbuh] said: ‘Leave him!’ So when he drew nearer, the Messenger of Allâh [pbuh] took the spear from Al-Harith bin As-Simma. He shivered violently in such a way that made all of them scatter in all directions violently and impulsively. Then he faced him, observed his clavicle through a gap between the wide opening of the armour and the part of his neck enclosed by. He speared him in that spot. The effect of the stroke was so strong that it made him roll off his horse over and over. When he returned to Quraish, they found that he had only had a small scratch in his neck. So when blood became congested he said: ‘By Allah, Muhammad has killed me.’ Hearing him say so, they said: ‘By Allâh you are afraid of death. By Allâh, you are possessed by a devil.’ He replied: ‘He had already told me when we were in Makkah: ‘I will kill you.’ By Allâh, had he spat on me, he would have killed me.’ Eventually, the enemy of Allah breathed his last at a place called Sarif, while they were taking him back to Makkah.” [Ibn Hisham 2/84; Za’d Al-Ma’ad 2/97]
In a version by Abul-Aswad, on the authority of ‘Urwa: He was lowing like a bull and saying: “By the One in Whose Hand is my soul, if (the pain) I am suffering from now were distributed among the people of Al-Majaz, it would cause them to die.” [Mukhtasar Seerat Ar-Rasool p.250]