'Day' in the Bible

Then Boaz said, On the day when you take this field, you will have to take with it Ruth, the Moabitess, the wife of the dead, so that you may keep the name of the dead living in his heritage.

And, further, I have taken Ruth, the Moabitess, who was the wife of Mahlon, to be my wife, to keep the name of the dead man living in his heritage, so that his name may not be cut off from among his countrymen, and from the memory of his town: you are witnesses this day.

And the women said to Naomi, A blessing on the Lord, who has not let you be this day without a near relation, and may his name be great in Israel.