They ask you about fighting during the Holy Month. Say, “Fighting during it is deplorable; but to bar others from God’s path, and to disbelieve in Him, and to prevent access to the Holy Mosque, and to expel its people from it, are more deplorable with God. And persecution is more serious than killing. They will not cease to fight you until they turn you back from your religion, if they can. Whoever among you turns back from his religion, and dies a disbeliever—those are they whose works will come to nothing, in this life, and in the Hereafter. Those are the inmates of the Fire, abiding in it forever.

The Holy Quran · Al-Baqara (The Cow) · 2:217