وَإِمَّا تَخَافَنَّ مِن قَوْمٍ خِيَانَةً فَٱنۢبِذْ إِلَيْهِمْ عَلَىٰ سَوَآءٍ ۚ إِنَّ ٱللَّهَ لَا يُحِبُّ ٱلْخَآئِنِينَ
4:108.
Commentary:
If a people with whom Muslims have entered into a covenant begin to commit acts of hostility towards them and it is feared that they are going to play false, then it should be openly and plainly declared to them that the covenant between them and the Muslims had come to an end. Then if, after such a declaration, they should fight the Muslims, the latter should also fight them. Thus Muslims are not allowed to make a surprise attack on any people without due notice. The Holy Prophet is reported to have said لا تفرط ولا تفجأ i.e. "Do not exceed the bounds in fighting, nor make a surprise attack on the enemy." Even in war, Islam enjoins strict justice and mercy.
4:108.
If a people with whom Muslims have entered into a covenant dishonour it, they should be plainly told that the covenant has come to an end and Muslims, if attacked, would fight back with all the force at their command. But under no circumstances are Muslims permitted to make a surprise attack, without giving a prior notice. ‘Ala Sawa’in means, on terms of equality, i.e. in such a manner that each party should know that it is free of its obligations.