What is "Chelkas ha'Sadeh"?
Ibn Ezra: It was a big field; part belonged to Elimelech 1 .
Malbim: It is part of the field, not the entire field. After the father and his sons died, Na'ami took part for her Kesuvah, and also Rus took part for her Kesuvah. First Bo'az informed Tov about Na'ami's portion; she wants to sell her half in Elimelech's field 2 .
Malbim: This is difficult, that he owned only a partial field.
Did Na'ami already sell the field?
Malbim: No. One may not redeem a Sedei Achuzah (ancestral inheritance) less than two years after it was sold 1 . Also, "b'Yom Kenosecha mi'Yad Na'ami" (5) implies that she already decided to sell and announced that she wants to sell it. It is destined to be sold; it is as if she already sold it to one who wants to buy it 2 .
Do not say that she sold it before leaving Eretz Yisrael. At the time, Elimelech owned it. Why would the sale be attributed to her?! (PF)
Malbim: Or, she wanted to sell, and I told her that I will tell you to buy. According to this, "Im Lo Yig'al" is Nistar (if he will not redeem). Bo'az tells Beis Din what he told Na'ami - I will tell him to redeem; if he will not
