Why does it say that they conquered Yerushalayim? It says already in Yehoshua (12:7, 10) that they conquered it! Also, in Yehoshua (15:63), it says that Bnei Yehudah could not dispossess the Yevusi there!
Radak: Here it means that they already conquered Yerushalayim.
Malbim: Melech Yerushalayim was the first of the five kings to fight against Giv'on. Yisrael killed him. They surely thought to capture his city, like the cities of the [other of the] five kings that they killed. Yehudah fought, for a strip including [part of] Yerushalayim is in its border. They could not dispossess the Yevusi there; they remained "Ad ha'Yom ha'Zeh", i.e. until the end of Yehoshua's lifetime; he wrote his Sefer. After Yehoshua died, there was war between them, and they captured it and burned it, to punish them for their rebellion. However, they did not capture the fortress called later Metzudas Tziyon, until the days of David. The Yevusi were also there. Binyamin did not fight them at all. Here (verse 21) it says that they remained with Binyamin "Ad ha'Yom ha'Zeh", i.e. until the end of Shmuel's lifetime; he wrote Sefer Shoftim.
What is the meaning of "v'Es ha'Ir Shilchu va'Esh"?
