Exodus 32:30 KJV
And it came to pass on the morrow, that Moses said unto the people, Ye have sinned a great sin: and now I will go up unto the Lord; peradventure I shall make an atonement for your sin.
Exodus 32:30, King James Version
In context
29 For Moses had said, Consecrate yourselves to day to the Lord, even every man upon his son, and upon his brother; that he may bestow upon you a blessing this day.
30 And it came to pass on the morrow, that Moses said unto the people, Ye have sinned a great sin: and now I will go up unto the Lord; peradventure I shall make an atonement for your sin.
31 And Moses returned unto the Lord, and said, Oh, this people have sinned a great sin, and have made them gods of gold.