Règle correspondante
Practice Relating to Rule 47. Attacks against Persons Hors de Combat
Jordan’s Military Penal Code (2002) states that the following shall be deemed a war crime when committed in the event of armed conflict: “Attacking persons hors de combat”. 
Jordan, Military Penal Code, 2002, Article 41(a)(13).
According to the Report on the Practice of Jordan, Islamic principles dictate that a combatant who is recognized as hors de combat may not be attacked. The report mentions an order of Caliph Abu Bakr, dating from the 7th century, which proscribed the killing of non-combatants. 
Report on the Practice of Jordan, 1997, Chapter 2.1. (The order was sent to the leader of the Muslim army fighting against the Romans in Greater Syria.)