Yes, I do know the history.
Do you have any comments on what I wrote or are you just going to ignore it?
I was going to ignore it! :) You asked "What,
or who, is the house of Israel and the house of Judah?", and then answered your own question with "I think the answer is the king". My response was that I believe it is referring to all of the tribes of Israel - all of God's chosen people. Therefore I don't think that it is referring the king.
But as you are asking for more comments ...
Regarding Isaiah 42:6, "I, Yahweh, have called you in righteousness, and will hold your hand, and will keep you, and make you a covenant for the people, as a light for the nations", this passage is refering to the nation of Israel, His servant (not Son, although it can be interpreted to be a Messianic prophecy too, as it mirrors Christ's work through them).
You quoted 2 Samuel 12:8, "I gave you your master’s house, and your master’s wives into your bosom, and
gave you the house of Israel and of Judah; and if that would have been too little, I would have added to you many more such things", claiming that king David "represents
in himself the house of Israel and the house of Judah". However, it is simply stating that God made David king over Israel and Judah:
2 Samuel (WEB):
2:4) The men of Judah came, and there they anointed David king over the house of Judah.
5:3) So all the elders of Israel came to the king to Hebron, and king David made a covenant with them in Hebron before Yahweh; and they anointed David king over Israel.
The Isaiah 42 passage is similar to Isaiah 49, which is also referring to the nation of Israel. Isaiah 49 (WEB):
(1) Listen, islands, to me. Listen, you peoples, from afar: Yahweh has called me from the womb; from the inside of my mother he has mentioned my name.
(2) He has made my mouth like a sharp sword. He has hidden me in the shadow of his hand. He has made me a polished shaft. He has kept me close in his quiver.
(3) He said to me, “You are my servant; Israel, in whom I will be glorified.”
(8) Yahweh says, “In an acceptable time I have answered you, and in a day of salvation I have helped you. I will preserve you, and give you for a covenant of the people, to raise up the land, to make them inherit the desolate heritage,
(9) saying to those who are bound, ‘Come out!’; to those who are in darkness, ‘Show yourselves!’ “They shall feed along the paths, and their pasture shall be on all treeless heights.
(10) They shall not hunger nor thirst; neither shall the heat nor sun strike them: for he who has mercy on them will lead them. He will guide them by springs of water.
(11) I will make all my mountains a road, and my highways shall be exalted.
(12) Behold, these shall come from afar; and behold, these from the north and from the west; and these from the land of Sinim.”
(13) Sing, heavens; and be joyful, earth; and break out into singing, mountains: for Yahweh has comforted his people, and will have compassion on his afflicted.
(14) But Zion said, “Yahweh has forsaken me, and the Lord has forgotten me.”
(15) “Can a woman forget her nursing child, that she should not have compassion on the son of her womb? Yes, these may forget, yet I will not forget you!
The "acceptable time" is, I believe, during the Millennial Age, after the resurrection of mankind has taken place, when Israel shall be God's chosen people on the earth, representing Him, and through whom Christ (the mediator of the New Covenant) will work. The nation of Israel will be "as a light for the nations" (42:6) and "will bring justice to the nations" (42:1). (God will not forget Israel [verse 15] - the Church replacing Israel is an erroneous belief). Isaiah 2 (WEB):
(1) This is what Isaiah the son of Amoz saw concerning Judah and Jerusalem.
(2) It shall happen in the latter days, that the mountain of Yahweh’s house shall be established on the top of the mountains, and shall be raised above the hills; and all nations shall flow to it.
(3) Many peoples shall go and say, “Come, let’s go up to the mountain of Yahweh, to the house of the God of Jacob; and he will teach us of his ways, and we will walk in his paths.” For out of Zion the law shall go out, and Yahweh’s word from Jerusalem.
(4) He will judge between the nations, and will decide concerning many peoples; and they shall beat their swords into plowshares, and their spears into pruning hooks. Nation shall not lift up sword against nation, neither shall they learn war any more.
Genesis 22:18 (WEB): "All the nations of the earth will be blessed by your [
Abraham's] offspring, because you have obeyed my voice.”
The Cambridge Bible notes on "a covenant of the people" says:
The most natural, and on the whole probably the most satisfactory rendering is, “a nation’s covenant,” i.e. the covenant upon which a nation is constituted, the conception implied being that Israel’s future national existence must be based on a new covenant between it and Jehovah (ch. Isaiah 55:3; Jeremiah 31:30-32). The difficulty is thus reduced to the pregnancy of the statement that the Servant is or shall be this covenant. It is probably to be explained in accordance with such expressions as “thou shalt be a blessing” (Genesis 12:2). As “blessing” there means “cause of blessing,” so here “covenant” may be equivalent to the ground or (as most commentators explain) the mediator of a national covenant. The idea at all events must be something like this: the Divine ideal represented by the Servant of the Lord becomes the basis of a new national life, inasmuch as it expresses that for the sake of which Jehovah enters into a new covenant relation with His people.