﴿ وَقَٰتِلُوا۟ فِى سَبِيلِ ٱللَّهِ ٱلَّذِينَ يُقَٰتِلُونَكُمْ وَلَا تَعْتَدُوٓا۟ ۚ إِنَّ ٱللَّهَ لَا يُحِبُّ ٱلْمُعْتَدِينَ ﴾

“AND FIGHT in God's cause against those who wage war against you, but do not commit aggression-for, verily, God does not love aggressors.”

The fighting (qital) mentioned here refers to that which took place during the life of the Prophet Muhammad. The Prophet’s Makkan opponents, not content with just expelling the Prophet and his companions from Makkah, their hometown, also prevented them from living and working peacefully in the neighbouring town of Yathrib (Madinah) where they had gone to settle. Without any provocation, they repeatedly attacked the Muslims who then had to fight in self-defence. When aggression has already been committed by opponents, believers are obliged to defend themselves. Initiating hostilities is not permitted for Muslims. Only defensive war is permitted in Islam. Even defensive war has to be openly declared by an established state.