2 Kings 5:9

Inwards. He built or repaired the higher "city of David," beginning at Mello, to "fill up" the valley, which Solomon finished, and adorned with a palace, 3 Kings ix. 15., and 4 Kings xii. 20. The place is probably called Asaramel, 1 Machabees xiv. 27. (Calmet)

Septuagint and Josephus generally understand Mello to designate the citadel of Sion, or "a complete fortification," to defend the city. Instead of inwards, the Septuagint have, "and his house." But ubithe means, "and to the house," temple, or fort, whence he began the enclosure, so as to make a complete communication. (Kennicott)

This city became "the most famous in all the East." (Pliny, [Natural History?] v. 14.)

"Walls, built in a crooked manner, according to the rules of art, enclosed two hills, immensely high." (Tacitus, Hist. v.)

These hills were multiplied, on account of their different summits, so that Josephus speaks of five hills. The palace of David stood on Sion, and the temple on Moria, which was a part of it still more elevated, towards the east. The other hill is often called Acra, by Josephus, and lay southward of Sion. Here the ancient town of Jebus was built. The Machabees took in an adjoining eminence. (Josephus, Jewish Wars vi. 6.)

Bethsetta, or the new city, was afterwards enclosed. Herod adorned the city with many superb monuments, both of a public and of a private nature. (Calmet)

We read of ten gates, and of four towers, belonging to this city. It was not well supplied with water, and what it had was brackish. The walls seem never to have exceeded four and a half miles; now they are only three, and include Mount Calvary, which was formerly no part of the city. Button says a valley run from west to east, between the two hills of Zion on the south, and Acra on the north; which contradicts the former statement. (Haydock)