References to Monks
On the authority of the Prophet's Companion Ibnu 'Abbas, Ahmad in his Musnad narrates that the Prophet صلى الله عليه وسلم, whenever he would send out an army, would generally instruct them with the following words:
لَا تَغْدِرُوا، وَلا تَغُلُّوا، وَلا تُمَثِّلُوا، وَلا تَقْتُلُوا الْوِلْدَانَ، وَلا أَصْحَابَ الصَّوَامِعِ
Do not breach trusts and do not defraud. Do not desecrate any corpses, nor kill any children, nor kill the monk-hut's inhabitants [i.e. the monks].
Besides readdressing the treatment of monks, the Prophet صلى الله عليه وسلم specifies further regulations. He prohibits the desecration of corpses, as well as the breaching of trusts or defrauding of an enemy.
Deducing that the breach of trust or fraudulence is forbidden, even if carried out against an enemy in times of war. However, Islam does not altogether forbid stratagem in war. Without having to elaborate the precise forms of stratagem defined in Islam, it is apparent that plain betrayal of an enemy, for example by breaching treaties or contracts, is not lawful and that Islamic law distinguishes cunning manoeuvre from treachery.
On the subject of monks, it is once again laid out by Ibnu Abi Shaybah:
عَنِ ابْنِ عَبَّاسٍ أَنَّ النَّبِيَّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ كَانَ إِذَا بَعَثَ جُيُوشَهُ قَالَ: «لَا تَقْتُلُوا أَصْحَابَ الصَّوَامِعِ»
On the authority of Ibnu 'Abbas, that, whenever the Prophet صلى الله عليه وسلم sent out an army, he used to instruct them: “Do not kill the inhabitants of monk-huts [i.e. monks]”
Muslims, undoubtedly, are bound to adhere to these commandments. Accordingly, Sa'id ibnu Mansur reports the following observations in his Sunan:
عَنْ بَكْرِ بْنِ سَوَادَةَ، أَنَّهُ قَالَ: «لَمْ نَرَ الْجُيُوشَ يُهَيِّجُونَ الرُّهْبَانَ الَّذِينَ عَلَى الْأَعْمِدَةِ، وَلَمْ نَزَلْ نُنْهَى عَنْ قَتْلِهِمْ إِلَّا أَنْ يُقَاتِلُوا»
On the authority of Bakr ibnu Sawadah, who said: “Not once did we witness the armies unsettling the monks on the columns. We were prohibited from killing them, except if they were fighting.”
“On the columns” possibly refers to the monk's huts, which were often situated on top of columns. This term could also refer to the pillars of temples.