Exodus 32:28 in the World English Bible
The sons of Levi did according to the word of Moses. About three thousand men fell of the people that day.
Context
27 And he said unto them, Thus saith the LORD God of Israel, Put every man his sword by his side, and go in and out from gate to gate throughout the camp, and slay every man his brother, and every man his companion, and every man his neighbour.
28 And the children of Levi did according to the word of Moses: and there fell of the people that day about three thousand men.
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.