Charles Ellicott Commentary Ruth 1:5

"And Mahlon and Chilion died both of them; and the woman was left of her two children and of her husband." — Ruth 1:5 (ASV)

And they died. —Clearly as quite young men. It is not for us to say how far those are right who see in the death of Elimelech and his sons God’s punishment for the disregard of His law. Thus Naomi is left alone, as one on whom comes suddenly the loss of children and widowhood.