'Rashi' writes that Elchanan is David. Why is he called Elchanan?
'Rashi': It is because Chanano Kel (Hashem had grace on him).
Why is he called here "Ben Ya'ir", and in Shmuel II, 21:19 'Ben Yarei Orgim"?
'Rashi': Ya'ir is like Ya'ar ha'Levanon 1 . It is proper that David, whose mother 2 wove the Paroches for the Beis ha'Mikdash 3 on the weavers' beam, kill Galyus, whose spear handle was like a weavers' beam!
Rus Rabah 2:2: His family used to weave the Paroches for the Mikdash, which is called Ya'ar. Radak (Shmuel II, 21:19) - it says "Ya'ar ha'Levanon 4 ", "Metzanuha bi'Sdei Ya'ar" (Tehilim 132:6). David's father Yishai is called Ya'ir, or Yarei, for he wove Parochos for Ya'ar.
Malbim (here and in Shmuel): He was from the family of Betzalel, the head of the weavers [for the Mishkan] and "Choshvei Machashavos" (Shemos 35:35). Also David was from this family, therefore he is called Efrati (Betzalel's great grandmother was Efrat (Miryam) - above, 2:19. Also David is from her - Sotah 11b.)
Rus Rabah 2:2: His family used to weave the Paroches for the Mikdash, which is called Ya'ar.
Surely 'Rashi' means the Mishkan. In Bayis Rishon, a Paroches covered the opening in the wall between the Kodesh and Kodesh ha'Kodoshim ? but David thought to build the Beis ha'Mikdash only after he was king over all of Yisrael (17:1). When David fled from Sha'ul, he left his parents with Melech Mo'av (Shmuel I, 22:4), who killed them! (PF).
This is difficult. This appears five times in Tanach (Melachim I, 7:2, 10:17, Divrei ha'Yamim II, 9:16, 20). Radak and all the Meforshim explain that it refers to Shlomo's house! - PF)
In Shmuel II, 21:19 Elchanan is called Beis ha'Lachmi; it says that he killed Galyus ha'Giti. Here it says that that he killed Es Lachmi, Galyus' brother. Also, David killed Galyus!
'Rashi': David killed Galyus ha'Pelishti; he is not Galyus ha'Giti 1 . The former was a son of Harafah. Verses 4 and 6 say that the man killed was mi'Yaldei ha'Refa'im (or Harafah). Since our verse does not say so, it does not discuss Galyus ha'Pelishti.
Radak: David killed Galyus ha'Pelishti; he is also Galyus ha'Giti, for he was from Gas. There, "Beis ha'Lachmi" refers to David [of Beis Lechem]; he killed Galyus. Elchanan killed Galyus' brother 2 . Here, Es Lachmi means with David, who is Lachmi; he helped Elchanan 3 to kill Galyus' brother.
Radak (Shmuel II, 21:19): There, Beis Lechem is like Im Beis Lechem (with David of Beis Lechem); Elchanan killed Es Galyus, i.e. the one who was with him, i.e. Galyus' brother, in Gov, and Beis ha'Lachmi (David) killed Galyus in Efes Damim (Shmuel I, 17:1). Here it says Es Lachmi; this is like mi'Lachmi, i.e. from Lachmi's sons, i.e. from the Giborim attributed to Beis Lechem, i.e. Elchanan. He killed Galyus' brother. 4
Vilna Gaon: "Es Lachmi" is like mi'Beis Lechem 5 . He killed Galyus; "Achi" means that he was the brother of Sipai mentioned in verse 4.
Malbim: Here, Ezra revealed that really, Elchanan killed Lachmi, who was a Gibor like his brother Galyus. Because David, also from Beis Lechem, killed him, people who make parables 6 said 'the Lachmi killed Galyus', to recall the similar Gevurah of David.
'Rashi' does not address why there it says Galyus, and here, his brother. (PF)
In Sefer Shmuel, Radak says that the verse there hints to killing both of them, or that both killed Galyus. Here he implies that it discusses only David killing Galyus. If so, why does it mention Elchanan? (PF)
Radak: It says (12:9) "u'Min ha'Gadi Nivdelu El David la'Metzad", i.e. from the Giborim attributed to Gad.
The verses say that David alone killed him! (PF)
This is like 'Rashi' explained, that Elchanan is David. (PF)
And the verse speaks like they do. (PF)
What is "ki'Mnor Oregim"?
'Rashi', Rashi and Targum Yonasan in Shmuel II, 21:19: It is the beam on which weavers arrange the warp (lengthwise) threads on a loom.
