What is the meaning of "Al Shadayim Sofedim"?
Rashi: They beat [themselves] over their hearts.
Rashi citing a Midrash: They eulogize over the Chachamim of the Sanhedrin, who are like breasts that nurse.
Radak: They eulogize over the breasts that dried amidst hunger.
Malbim: Now they are naked of their garments. They eulogize - if only she were a naked infant - at least she nurses from her mother's breasts! This is a metaphor - if only they had their fields to provide food, even though they are naked.
What is "Al Sedei Chemed"?
Rashi: On their coveted fields.
Rashi citing a Midrash: They eulogize over their coveted city, which will be plowed like a field.
Radak: They eulogize over the lack of bread; the coveted fields that they used to have are now fallow.
Why does it say "Al Gefen Puriyah"?
Rashi citing a Midrash: They eulogize over Yisrael, who are called Gefen - "Gefen mi'Mitzrayim Tasi'a" (Tehilim 90:9).
Radak: They eulogize over the lack of wine; the fruitful vine that they used to have is now empty.