Deuteronomy 9:11

And it came to pass at the end of forty days and forty nights,
&c.] The time of Moses's stay in the mount, when it was just up, and not before: that

the Lord gave me the two tables of stone, [even] the tables of the
covenant,
as in ( Deuteronomy 9:9 ) . Aben Ezra observes, that this shows that the day the tables were given to Moses the calf was made.