Albert Barnes Commentary 1 Chronicles 27:25-31

"And over the king`s treasures was Azmaveth the son of Adiel: and over the treasures in the fields, in the cities, and in the villages, and in the castles, was Jonathan the son of Uzziah: And over them that did the work of the field for tillage of the ground was Ezri the son of Chelub: and over the vineyards was Shimei the Ramathite: and over the increase of the vineyards for the wine-cellars was Zabdi the Shiphmite: and over the olive-trees and the sycomore-trees that were in the lowland was Baal-hanan the Gederite: and over the cellars of oil was Joash: and over the herds that fed in Sharon was Shitrai the Sharonite: and over the herds that were in the valleys was Shaphat the son of Adlai: and over the camels was Obil the Ishmaelite: and over the asses was Jehdeiah the Meronothite: and over the flocks was Jaziz the Hagrite. All these were the rulers of the substance which was king David`s." — 1 Chronicles 27:25-31 (ASV)

This section is important because it shows that David, the younger son of a not very wealthy family (1 Samuel 16:11, 20), had become a large landowner and a man of great capital, possessing much movable wealth.

We can see the sources of his property in the successful wars he waged (1 Samuel 27:8–9; 1 Samuel 30:20; 2 Samuel 8:4, 7–8, 12), in the revenue from subject kings (2 Samuel 8:2, 14; 10:19), and in his purchase and occupation of lands in various places. Furthermore, he enjoyed the usual rights of a Jewish king over the landed property of his subjects. This entitled him to receive a tenth of the produce in tithes (1 Samuel 8:15, 17) and in “benevolences,” or special gifts (compare 1 Samuel 10:27; 16:20).

1 Chronicles 27:25

The castles: These were probably the watchtowers in the border districts, which were exposed to raids from the plundering tribes of the desert (2 Chronicles 26:10; 2 Chronicles 27:4).

1 Chronicles 27:28

In the low plains: This should be translated as “in the Shephelah,” which is the proper name for the low tract of land between the hill country of Judea and the Mediterranean.