Nasai

Benefits and Issues:
(1)
The Prophet (sallallahu alayhi wa sallam) understood from the words of the one who whispered that this person was not a Muslim at heart, but later, relying on his outward Islam, he let him go. Imam Suyuti (rahimahullah) writes regarding this: The more correct explanation is that the Messenger of Allah (sallallahu alayhi wa sallam) was permitted to treat someone according to his inner state, and thus he intended to act accordingly (to kill him on account of disbelief). Then the Prophet (sallallahu alayhi wa sallam) deemed it better to act upon the apparent (to treat him as a Muslim due to his outward Islam), because this law is for both the Prophet (sallallahu alayhi wa sallam) and the entire Ummah, so he inclined towards this and refrained from acting according to the inner (true state). (Sharh Sunan al-Nasa’i, Kitab Tahrim al-Dam)

(2)
In this chapter of Sunan al-Nasa’i, a similar incident is also narrated from Hazrat Aws (radi Allahu anhu). Hazrat Aws (radi Allahu anhu) reports: I came to the Messenger of Allah (sallallahu alayhi wa sallam) as part of the delegation of the tribe of Thaqif. I was in the tent with the Messenger of Allah (sallallahu alayhi wa sallam). All the people in the tent except me and the Prophet (sallallahu alayhi wa sallam) had fallen asleep. (During this time of solitude) a man came and spoke in a whisper. The Prophet (sallallahu alayhi wa sallam) said: Go and kill him. Then he said: Does he not bear witness to La ilaha illallah and to my Messengership? He said: He does bear witness. The Messenger of Allah (sallallahu alayhi wa sallam) said: Leave him. Then he said: I have been commanded to fight the people until they say La ilaha illallah. When they affirm this, their blood and their wealth become forbidden (to the Muslims) except by right. (Sunan al-Nasa’i, al-Muharaba, Chapter: Prohibition of Blood, Hadith: 3987)

“They become worthy of respect”—meaning, they cannot be killed, injured, dishonored, nor can their wealth be taken without their consent. However, if there is a rightful claim upon them, it must be fulfilled; for example, if they have killed or injured someone, they will have to pay retribution (qisas) or blood money (diyah). Similarly, if there is a financial right due from them, the government will ensure its payment, even by force if necessary.