A walled city that was located on the boundary between Judah and Benjamin. David conquered it, and afterward it became known as the "city of David," or ancient Jerusalem. The people who lived there were called Jebusites (Joshua 18:16). They were one of several groups collectively known as Canaanites (Genesis 10:15–16).
God repeatedly promised the land of the Jebusites and their neighbors to the Israelites (Exodus 3:8; 13:5; 23:23; 33:2; 34:11; Numbers 13:29; Deuteronomy 7:1; 20:17). This promise was partly fulfilled early in the campaign led by Joshua (Joshua 3:10; 12:8; 18:16; compare 24:11). The Bible says that the men of Judah fought against Jerusalem and took it (Joshua 18:28). "The Benjamites, however, failed to drive out the Jebusites living in Jerusalem. So to this day the Jebusites live there among the Benjamites" (Judges 1:21). It seems the city was captured by the men of Judah, but its people were not destroyed and they later moved back to the site.
Jebus (or Jerusalem) was on the border between two tribes, Judah and Benjamin. This may explain why it survived until the time of David. The borders of Judah and Benjamin are described this way: "the border went up the Valley of Hinnom along the southern slope of the Jebusites (that is, Jerusalem) and ascended to the top of the hill that faces the Valley of Hinnom on the west, at the northern end of the Valley of Rephaim" (Joshua 15:8). It then "ran down the Valley of Hinnom toward the southern slope of the Jebusites and downward to En-rogel" (Joshua 18:16). Both descriptions agree that Jebus was on the southern slope of the "mountain" north of the valley of Hinnom. This is where East Jerusalem is today.
The city survived because it had a constant water supply from the spring of Gihon. It also had strong natural defenses. It was easy to defend because of steep valleys on three sides: the Kidron to the east and the Hinnom to the south and west. The Jebusites thought their city could not be captured. This made them proud and self-satisfied. After Saul died, when David was trying to unite the kingdom, the Jebusites mockingly challenged David to capture their stronghold (2 Samuel 5:6; compare 1 Chronicles 11:5). As the last remaining Canaanite stronghold in the area, it presented a unique challenge. Joab apparently led the attack up the water shaft and succeeded where previous attempts had failed (2 Samuel 5:8).
For both political and strategic reasons, David decided to move his capital from Hebron to Jebus. Politically, it was in neutral territory between Judah and Benjamin so it did not cause jealousy among the tribes. Strategically, it was easy to defend and more centrally located. The choice proved to be wise. Despite the fact that Jebus-Jerusalem is not on any waterway or major road, it has become through the centuries the spiritual capital of the world. Under David and Solomon, it became Israel's religious center, and today it is very important to the three major religions that believe in one God (Judaism, Christianity, and Islam).