1 Kings 6:16 - Joseph Benson’s Commentary on the Old and New Testaments

He built twenty cubits on the sides of the house He speaks here of the most holy place, which contained in length twenty cubits, and might be said to be on the sides of the house, because it took off twenty cubits in length from each side of the house, and was also twenty cubits from side to side, so it was twenty cubits every way. He built them for it within, even for the oracle, the most holy place The last words are added to explain what he means by the word oracle, which he had not used before: this was the most important of all the parts of the house, because here the divine glory was present, and from hence God gave answers when he was consulted, on which account it is termed the oracle.