John Gill Commentary Exodus 32:31

"And Moses returned unto Jehovah, and said, Oh, this people have sinned a great sin, and have made them gods of gold." — Exodus 32:31 (ASV)

And Moses returned unto the Lord
On the mount where he was in the cloud:

and said, oh, this people have sinned a great sin ;
which to following words explain; he confesses the same to God he had charged the people with in (Exodus 32:30) :

and have made them gods of gold ;
the golden calf, which they themselves called "Elohim", gods.