Al-Miqdad b. al-Aswad told that he said, “Tell me, Messenger of God, supposing I meet an infidel and we fight together and he strikes one of my hands with his sword and cuts it off, then flies for refuge from me to a tree and says he has submitted himself to God (or, in another version, says when I intend to kill him that there is no god but God), shall I kill him after he has said it?” He replied, “Do not kill him.” He protested, “But, Messenger of God, he cut off one of my hands.” God’s Messenger then replied, “Do not kill him, for if you do so, he will be in the position in which you were before you killed him, and you will be in the position in which he was before he made his testimony.”*
(Bukhari and Muslim.)
*i.e. he will now be one for whose killing retaliation may be demanded, and you will be one whose blood may lawfully be shed.
‘Abdallah b. Mas'ud reported God’s Messenger as saying, “Shedding of blood will be the first matter about which judgment will be given on the day of resurrection.”
God’s Messenger sent us to some people of Juhaina, and I attacked one of them and was about to spear him when he said, “There is no god but God.” I then speared him and killed him, after which I went and told the Prophet. He said, “Did you kill him when he had testified that there is no god but God?” I replied, “Messenger of God, he did that only as a means to escape death.” He asked, “Why did you not split his heart?”*
(Bukhari and Muslim.)
*He is here rebuked for attributing motives to the man when he could not know his inner motive. Splitting the heart is a figure of speech for examining the inner motives.
In the version of Jundub b. ‘Abdallah al-Bajali God’s Messenger is reported as saying several times, “How will you deal with ‘There is no god but God’ when it comes on the day of resurrection?”
Ibn ‘Umar reported God’s Messenger as saying, “A believer will continue to find ample scope in his religion as long as he does not kill anyone unlawfully.”