Indeed, according to the highly respected Qur'anic exegesis of Ibn Kathir- early qur'anic commentator and Tabi‘un, Sayid ibn Jubayr (who lived at the time of Muhammad, and was a companion of Ayesha), had said:

"He who allows himself to shed the blood of a Muslim, is like he who allows shedding the blood of all people. He who forbids shedding the blood of one Muslim, is like he who forbids shedding the blood of all people."