Was the ruling "A believer shall not kill a disbeliever, nor shall a disbeliever be supported against a believer," mentioned in the Document of Medina, limited to the time the document was issued, or is it a general ruling until now? And if it is a general ruling, how can it be reconciled with the Almighty's saying (Whoever kills a soul unless for a soul or for corruption [done] in the land - it is as if he had slain mankind entirely), especially if the Muslim is a murderer and the disbeliever is peaceful?

Ibn Ishaq mentioned that the Prophet, peace and blessings be upon him, wrote a document between the Muhajireen and the Ansar and made a treaty with the Jews. This document was mentioned by Ibn Abi Khaythama with a weak chain of transmission, and it has a disconnected and also weak corroborating report.

The statement "A believer shall not be killed for an unbeliever, nor shall an unbeliever be aided against a believer" (لا يُقتل مؤمن في كافر، ولا يُنصر كافر على مؤمن) has its meaning established in the Sunnah (definition). It provides an exception to the general verses of Qisas (retaliation). The majority of scholars are of the opinion that a Muslim is not killed for an unbeliever; rather, the Muslim killer is punished by discretionary punishment (ta'zeer) and pays the blood money (diyah) of the slain. Unjustly killing a soul is one of the major sins.