Sayyiduna Ma'qil bin Yasar (may Allah be pleased with him) said: I heard the Prophet (peace and blessings be upon him) say: "There is no servant who is made the guardian of a flock (of people) and is treacherous towards them, except that he will enter the Fire."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17583