Tafsir of Ta-Ha 20:95

How As-Samiri made the Calf Allah tells,

قال فما خطبك يا سامري

(Musa) said: "And what is the matter with you. O Samiri!'' Musa said to As-Samiri, "What caused you to do what you did What presented such an idea to you causing you to do this!'' Muhammad bin Ishaq reported from Ibn Abbas that he said, "As-Samiri was a man from the people of Bajarma, a people who worshipped cows. He still had the love of cow worshipping in his soul. However, he acted as though he had accepted Islam with the Children of Israel. His name was Musa bin Zafar.'' Qatadah said, "He was from the village of Samarra.''