In his absence the nation of Musa (Moses) made an image of a calf for worship from their jewelry which produced a mooing sound. Did they not see that it could neither speak to them nor give them the guidance? Yet they took it for worship and became wrongdoers.
Meaning:-
Calf: a young cow,
Moo: the sound that a cow makes
Wrongdoer: a person who behaves illegally or dishonestly; an offender.