Charles Ellicott Commentary Ruth 4:5

"Then said Boaz, What day thou buyest the field of the hand of Naomi, thou must buy it also of Ruth the Moabitess, the wife of the dead, to raise up the name of the dead upon his inheritance." — Ruth 4:5 (ASV)

What day ... —When the person had been bought out to whom Naomi had sold the land (this sale lasting until the Year of Jubilee would restore it to her family), Naomi’s own claim on the land remained, and afterwards that of Ruth, as the widow of Elimelech’s son. But further, this last carried with it the necessity of taking Ruth to wife, so that a child might be born to inherit, as Mahlon’s son, Mahlon’s inheritance.