C. F. Keil and Franz Delitzsch on 2 Chronicles 3:8-9

2Ch 3:8-9 The most holy place, with the figures of the cherubim and the veil; cf. 1Ki 6:19-28. - The length of the most holy place in front of the breadth of the house, twenty cubits, consequently measured in the same way as the porch (2Ch 3:4); the breadth, i.e., the depth of it, also twenty cubits. The height, which was the same (1Ki 6:20), is not stated; but instead of that we have the weight of the gold which was used for the gilding, which is omitted in 1 Kings 6, viz., 600 talents for the overlaying of the walls, and 50 shekels for the nails to fasten the sheet gold on the wainscotting. He covered the upper chambers of the most holy place also with gold; see 1Ch 28:11. This is not noticed in 1 Kings 6.