King James Version
And be ready against the third day: for the third day the LORD will come down in the sight of all the people upon mount Sinai.New International Version
and be ready by the third day, because on that day the LORD will come down on Mount Sinai in the sight of all the people.Catholic Public Domain Version
And let them be prepared on the third day. For on the third day, the Lord will descend, in the sight of all the people, over Mount Sinai