A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
2 Chronicles 9:1
ch2 9:1THE QUEEN OF SHEBA VISITS SOLOMON; SHE ADMIRES HIS WISDOM AND MAGNIFICENCE. (Ch2 9:1-12)
when the queen of Sheba heard of the fame of Solomon--(See on Kg1 10:1-13). It is said that among the things in Jerusalem which drew forth the admiration of Solomon's royal visitor was "his ascent by which he went up into the house of the Lord." This was the arched viaduct that crossed the valley from Mount Zion to the opposite hill. In the commentary on the passage quoted above, allusion was made to the recent discovery of its remains. Here we give a full account of what, for boldness of conceptions for structure and magnificence, was one of the greatest wonders in Jerusalem. "During our first visit to the southwest corner of the area of the mosque, we observed several of the large stones jutting out from the western wall, which at first seemed to be the effect of a bursting of the wall from some mighty shock or earthquake. We paid little regard to this at the moment; but on mentioning the fact not long after to a circle of our friends, the remark was incidentally dropped that the stones had the appearance of having once belonged to a large arch. At this remark, a train of thought flashed across my mind, which I hardly dared to follow out until I had again repaired to the spot, in order to satisfy myself with my own eyes as to the truth or falsehood of the suggestion. I found it even so. The courses of these immense stones occupy their original position; their external surface is hewn to a regular curve; and, being fitted one upon another, they form the commencement or foot of an immense arch which once sprung out from this western wall in a direction towards Mount Zion, across the TyropÅon valley. This arch could only have belonged to the bridge, which, according to JOSEPHUS, led from this part of the temple to the Xystus (covered colonnade) on Zion; and it proves incontestably the antiquity of that portion from which it springs" [ROBINSON]. The distance from this point to the steep rock of Zion ROBINSON calculates to be about three hundred and fifty feet, the probable length of this ancient viaduct. Another writer adds, that "the arch of this bridge, if its curve be calculated with an approximation to the truth, would measure sixty feet, and must have been one of five sustaining the viaduct (allowing for the abutments on either side), and that the piers supporting the center arch of this bridge must have been of great altitude--not less, perhaps, than one hundred and thirty feet. The whole structure, when seen from the southern extremity of the TyropÅon, must have had an aspect of grandeur, especially as connected with the lofty and sumptuous edifices of the temple, and of Zion to the right and to the left" [ISAAC TAYLOR'S EDITION OF TRAILL'S JOSEPHUS].
2 Chronicles 9:13
ch2 9:13HIS RICHES. (2Ch. 9:13-28)
Now the weight of gold that came to Solomon in one year--(See on 1Ki. 10:14-29).
six hundred and threescore and six talents of gold--The sum named is equal to Â£3,646,350; and if we take the proportion of silver (Ch2 9:14), which is not taken into consideration, at one to nine, there would be about Â£200,000, making a yearly supply of nearly Â£6,000,000, being a vast amount for an infant effort in maritime commerce [NAPIER].
2 Chronicles 9:21
ch2 9:21the king's ships went to Tarshish--rather, "the king's ships of Tarshish went" with the servants of Huram.
ships of Tarshish--that is, in burden and construction like the large vessels built for or used at Tarshish [CALMET, Fragments].
2 Chronicles 9:25
ch2 9:25Solomon had four thousand stalls--It has been conjectured [GESENIUS, Hebrew Lexicon] that the original term may signify not only stall or stable, but a number of horses occupying the same number of stalls. Supposing that ten were put together in one part, this would make forty thousand. According to this theory of explanation, the historian in Kings refers to horses [see Kg1 10:26]; while the historian in Chronicles speaks of the stalls in which they were kept. But more recent critics reject this mode of solving the difficulty, and, regarding the four thousand stalls as in keeping with the general magnificence of Solomon's establishments, are agreed in considering the text in Kings as corrupt, through the error of some copyist.
2 Chronicles 9:28
ch2 9:28they brought unto Solomon horses out of Egypt--(See on Ch2 1:14). Solomon undoubtedly carried the Hebrew kingdom to its highest pitch of worldly glory. His completion of the grand work, the centralizing of the national worship at Jerusalem, whither the natives went up three times a year, has given his name a prominent place in the history of the ancient church. But his reign had a disastrous influence upon "the peculiar people," and the example of his deplorable idolatries, the connections he formed with foreign princes, the commercial speculations he entered into, and the luxuries introduced into the land, seem in a great measure to have altered and deteriorated the Jewish character.