Charles Ellicott Commentary 1 Kings 8:56

"Blessed be Jehovah, that hath given rest unto his people Israel, according to all that he promised: there hath not failed one word of all his good promise, which he promised by Moses his servant." — 1 Kings 8:56 (ASV)

That has given rest. Now, for the first time, the frequent promise of rest (Exodus 33:14; Deuteronomy 12:10, and other passages)—a promise partially fulfilled after the conquest in the days of Joshua (Joshua 21:44–45; Joshua 23:1; Joshua 23:14) and after the establishment of David’s kingdom (2 Samuel 7:1)—was perfectly accomplished under Solomon the Peaceful. At this time also, the entire charter of gift of the promised land (Joshua 1:3–4) was for the first time fully entered into. Of the “rest” of Israel, the transfer of the Ark of the Lord from the shifting Tabernacle to the fixed Temple was at once a sign and a pledge.

Yet Solomon’s subsequent words imply that “entering into that rest” was conditional on fulfillment of Israel’s part in the covenant, by “walking in the ways of the Lord.” That condition, which he knew so well, he himself broke, and all Israel with him. Hence the fulfillment of the foreboding which emerges so constantly in his prayer. The glory of rest and happiness of his age was but a gleam of prosperity, soon to be swallowed up in dissension and disaster.