The Islamic Personality by Sheikh Taqīuddīn An-Nabahānī

The armistice treaty between Muslims and disbelievers is permitted due to his (saw) truce with Quraysh in the year of Hudaybiyya. However the permissibility of a truce is restricted to the existence of benefit for which the jihad or spreading of the da’wah requires it. This is because it reached the Messenger of Allah (saw) before his travelling to Hudaybiyya that an agreement had been made between the people of Khayber and Makkah upon invading the Muslims. He hastened directly upon his return from Hudaybiyya to invade Khayber and similarly hastened to send messengers to the kings and leaders inviting them to Islam which indicates that the truce of Hudaybiyya was for a benefit related to jihad and spreading the da’wah. After coming into a truce with Quraysh he was able to free himself for fighting Khayber and for performing the da’wah to the kings and leaders. The truce is not allowed in the absence of this benefit since a truce is leaving the obligated fighting which is not allowed except in the situation it occurs as a means to fighting as at this point it becomes fighting metaphorically. Allah (swt) said:

If the benefit in an armistice treaty is verified, it must be measured for a specified and known period. No truce is allowed without measuring a period because it is a fixed period contract so leaving it unrestricted without mentioning the period invalidates it due to its necessitating permanency which is prevented in the armistice treaty so that jihad remains constant as its permanency prevents jihad which is obligatory. Measuring a specific period in the truce is a condition of its validity so if no specific period is measured for it, this invalidates the armistice treaty since the Hudaybiyya armistice had a specific period measured for it. If the armistice is contracted and it is valid, it is obliged upon us to abstain from them and observe the armistice treaty until its period concludes or they violate it with their nullifying it either by their saying so clearly, fighting us, killing a Muslim or a dhimmi in our land or something is done contradicting the armistice’s conditions and the rest do not reject this from him by word(s) or action(s). If this occurs, the truce is nullified in all of these. Similarly if the State fears their treachery by something which invalidates their show of the truce such as when a sign of this appears; this would be nullification of the truce. If something like this occurs, a surprise attack against them is allowed any time, night or day, since their breaking the truce allows the Muslims to fight them and to nullify the truce with them. This is because when the Messenger (saw) came to a truce with Quraysh and they broke his truce, all what was forbidden in the truce period became permitted so he fought them and conquered Makkah. Also because the truce is a fixed period contract which ends with its period finishing or its nullification. Allah (swt) said:

:And He (swt) said"

And He (swt) said:

If the enemy falls short of the truce’s conditions and does not observe their agreement in their transactions with us, then they have absolved us from our covenant. Due to this their blood and property have no sanctity, and fighting them is obligatory upon us. So it is obligatory upon us to fight them since they fought us, and to annul the truce with them since they violated it.