John Gill Commentary 1 Kings 8:51

"(for they are thy people, and thine inheritance, which thou broughtest forth out of Egypt, from the midst of the furnace of iron);" — 1 Kings 8:51 (ASV)

For they be your people, and your inheritance
Whom the Lord had chosen above all people, to be a special people to him, and to be his portion and possession; see (Deuteronomy 7:6) (32:9)

which you brought forth out of Egypt, from the midst of the furnace
of iron; hard and cruel bondage in Egypt: (See Gill on Deuteronomy 4:20).