What is the Book of Kings about? What's in it?
Kings is an account of (what else?) kingship in ancient Israel. It includes the history of the monarchy from its high point in a mostly unified kingdom to its low point in the Babylonian Exile. One simple way of outlining the book presents it in three parts:
A. The reign of Solomon (1 Ki. 1-11): his accession (chapters l-2), his successes (3-10), his failures (11).
B. The divided kingdom (1 Ki. 12 through 2 Ki. 17): Judah under Rehoboam, and the majority of the northern tribes under Jeroboam who retain the title "Israel," separate from each other. Israel comes under considerable pagan influence from the beginning and experiences many bloody coups before finally being exiled. Judah is less paganized, though only preserved because of God's faithfulness to his promise to David. The prophets Elijah and Elisha are heavily involved, especially in the story of Israel, the northern kingdom.
C. The kingdom of Judah (2 Ki. 18-25): despite the reforms of Hezekiah and Josiah, the paganizing policy of Manasseh finally bears fruit in the fall of Judah too. But the conclusion of the book sounds a possible note of hope (25:27-30).
Where did the Book of Kings come from? Who wrote it and when?
This is one of those many places where we have much less information than we would like to have. The last event to which Kings refers is the exiled king Jehoiachin’s release from prison in Babylon in 561 B.C. (2 Ki. 25:27). Clearly, the book in its final form comes from after this time. We do not know the name of the author(s) of Kings.
What sort of book is this? How does it "work"?
Kings proceeds as a reign-by-reign treatment of the history. During the period of the divided kingdom, the accounts of northern and southern kings are allowed to interweave. Each king is described and evaluated according to a consistent pattern, which can be seen by looking at the short accounts of the reign of Jehoshaphat (1 Ki. 22:41-50) or Amon (2 Ki. 21:19-26). But sometimes, this "description and evaluation" is the framework which is filled by and surrounded by other material. Sometimes the opening and closing statements are separated by several chapters. For example, the accounts of Solomon, Rehoboam, Ahab, Jehoram, Jehu and Joash, include a lot of material focused on various aspects of Israelite politics. Other sections focus on prophets, especially Elijah, Elisha, and Isaiah.
Why was Kings written? What's the message?
First, the purpose of Kings is to review the history which led up to the Exile, and to explain why the Exile happened. The Book also serves as a kind of national confession: there was every reason for God to judge Israel and to send his chosen nation into exile.
Second, Kings also delivers a message of hope. For example, the end of the book seems to say, "Maybe God’s commitment to David still holds." It may be that the release of Jehoiachin--related in the final paragraph of Kings-- is there to keep Israel's hope alive. Although the Temple has been pillaged and burnt, prayer is still possible in the Temple (or towards it on the part of people who are cut off from it), and God has decided to hear such prayer. Although judgment has come in keeping with the warnings of the covenant, the same covenant allows for the possibility of repentance and restoration after judgment (see 1 Ki. 8:46-53 and compare Deuteronomy 30). Although the prophetic words which Israel ignored are another reason for her punishment, the fact that those prophetic words of judgment have come true may encourage a hope that the prophetic promises of restoration will also come true.
Third, the Book of Kings pictures God’s involvement in political life, and warns against under-valuing the significance of political structures, and against over-emphasizing them. Kings reveals how God brings judgment on any kingdom. The book also displays the interplay of the free determination of human beings (who in various political situations makes their decisions and put their policies into effect) and the free decision of a sovereign God (who nevertheless effects his will through, or in spite of, human actions). To get a handle on this paradox, we might ask: Are individuals the masters of their own destinies? Or does God finally determine every outcome? The answer seems to be "Both." In fact, in Kings, any attempt to make it absolutely one or the other runs into problems. So where does that leave us? It leaves us with the confidence that God works out a purpose in history in spite of what people, even his people, might do.
Fourth, a basic teaching of the Torah, especially the Book of Deuteronomy, is that God blesses those who are faithful to him but brings trouble to those who disobey him (see, for example, Deuteronomy 28-30). This is a major theme in Kings. Thus the material concerning Solomon’s reign is arranged so that Solomon’s setbacks are understood as consequences of his association with foreign women (1 Ki. 11). On the other hand, Kings recognizes that God's justice does not work out this way in every case. The wicked Manasseh enjoys a long reign, and his apostasy only brings its fruit decades later (2 Ki. 21; 24:3-4). Josiah is responsive to God’s word, but dies an early and tragic death (2 Ki. 23:29).
As I see the Book of Kings, these seem to be the basic messages.