Targum zu Schemot 32:5

For Aharon had seen Hur slain before him, and was afraid; and he builded an altar before him, and Aharon cried with doleful voice, and said, Let there be a feast before the Lord tomorrow, of the sacrifice of the slain of these adversaries who have denied their Lord, and have changed the glory of the Shekinah of the Lord for this calf.

And Aharon saw Hur slain before him, and was afraid; and he builded an altar before him, and Aharon cried and said, A feast.