What is "Pas Damim"?
'Rashi': It is a place. In Shmuel I, 17:1 it is called "Efes Damim." Radak ? also the episode with Galyus was there. In Shmuel II, 23:11 it is called Chayah, a city without a wall.
Why did the Pelishtim gather to fight?
'Rashi': This was to avenge the Giborim who disgraced them (Shmuel II, 23:9).
What is the significance that it was a field of barley?
'Rashi': The Pelishtim wanted to harvest it and burn it.
Here it implies that Elazar struck Pelishtim with David in Pas Damim. In Shmuel II, 23:12, it says that Shama ben Age struck them!
Radak #1: Really, Shama ben Age struck them, like it says there. Since it mentioned the three Giborim, and he was the third, it is as if he was mentioned.
Radak #2: Perhaps Elazar was with Shama; it says (verse 14) "va'Yisyatzvu" (plural). Shamah was primary, therefore only he is mentioned in Shmuel.
Vilna Gaon (14): Elazar saved a barley field, and Shamah saved a lentil field. Malbim - Ezra did not need to teach here what is explicit in Sefer Shmuel. Sefer Shmuel did not mention Elazar, for he did not save it alone (refer to 11:14:1:3).
Malbim (Shmuel II, 23:10): Elazar began, and Shama ben Age finished. Here it is concise, so it attributes the victory only to Elazar, for he began.
Here it says that the field was full of barley. Why does it say in Shmuel II, 23:11 that the field was of lentils?
(Rav Huna) Bava Kama 60b: There were stacks of barley and of lentils. Radak ? the field was already harvested. The stacks of barley and lentils were from other fields. In each place, the verse mentions one of them.
Radak (Shmuel II, 23:16, citing Bava Kama 60b): There were stacks of barley of Yisrael, and stacks of lentils of Pelishtim.
Radak (Shmuel II, 23:16, citing Yerushalmi Sanhedrin 12b): This occurred in one year. One field was full of barley, and another field was full of lentils.
Radak (Shmuel II, 23:16, citing Yerushalmi Sanhedrin 12b): This occurred in two years. In one year, the field was full of barley. In the other year, it was full of lentils.
Malbim: Elazar was in the barley field, and Shamah was in the lentil field.
