Allah 's Apostle said, " I have been ordered to fight with the people till they say, 'None has the right to be worshipped but Allah,' and whoever says, 'None has the right to be worshipped but Allah,' his life and property will be saved by me except for Islamic law, and his accounts will be with Allah, (either to punish him or to forgive him.)" (Using translation from Bukhārī 2946)
"أمِرْتُ أنْ أقاتِلَ الناسَ حَتَّى يَقُولوا: لَا إلَهَ إلَّا اللهُ فَمَنْ قال: لَا إله إلَّا اللهُ فقد عَصَم منّي ماله ونفْسَه إلَّا بِحقه، وَحِسابُه على اللهِ".