The Gemora asks from a braisa: From the implication of the verse (discussing those who oppress widows and orphans): “And I shall become incensed, and I shall kill you with the sword,” I know that their wives shall be widows and their children shall be orphans; why then does the Torah state: “And your wives shall be widows, and your children shall be orphans”? This teaches us that their wives will seek to remarry and we will not permit them (for Hashem is cursing them that they will be taken captive and we will not know if they died or not), and their children will desire to go down to their father’s property and we will not allow them. [This contradicts Shmuel, who rules that we do allow the relatives to go down to the captive’s field!?]
Rava answers: The braisa means that they are not permitted to go down and sell the property.
The Iyun Yaakov asks: What is the curse to the dead sinner if his wife will not be allowed to remarry? There is no pain at all! On the contrary, the Zohar writes that this would be regarded as an honor to the deceased!?
He answers that nevertheless, at the time that the woman desires to remarry, she will be embarrassed, and Chazal say that a man does not want his wife humiliated before a Beis Din!
The Ben Yehoyada writes that these men were killed by sword and buried immediately. There were no witnesses available to verify their identity. It will therefore be necessary to open their graves to see if there are any identifying marks to help us determine who they were. This is considered painful to the deceased, and this is the meaning of the curse.
He adds that these women, who will never be allowed to remarry, will eventually curse their own husbands for being the cause of their present predicament. This will be painful for the deceased!