Let’s start at the very beginning

In the beginning, God created, man rebelled, but God repeatedly promised to redeem and restore. From Gen 3:15 to Noah to Abraham to Jacob to Moses, we see God covenanting with His chosen people, who by no means could save themselves. As we know, Israel spent several centuries under cruel slavery in Egypt, but through Moses and Aaron, God delivered His people with incredible miracles. By the end of the Pentateuch (first five books of the bible, authored by Moses), Israel is wandering in the desert, on the brink of inheriting the promised land. Deuteronomy was devoted almost entirely to renewing God’s covenant with Israel; way more important than occupying the land was whether Israel would remain obedient and faithful to her loving God.  

The book of Joshua sees Israel entering and taking over the promised land, by God’s mighty arm. Sadly, Israel quickly forgets her God and Judges describes her continual running away and back again, receiving mercy and deliverance from Yahweh every time, yet never able to stay faithful for long. Samuel was the last of the judges, by which time Israel, apparently sick of the judges, asked for a human king to rule them, just like all the other pagan nations had. God gave them what they asked for, but not without warnings.

Overviews

The book of Samuel (originally written as one volume, later divided into two, as was Kings and Chronicles) covers the transition from Samuel, the last judge, to Saul the first king, and then to king David. The contrast between Saul and David needs no emphasis. David was a king who was truly after God’s heart, and God accordingly promised that David’s kingdom would endure forever (2 Sam 7:5-16). That promise was completely kept, because although there is no earthly king descended from David currently ruling in the world, Jesus, the great and true King in the line of David has already come to establish his eternal Kingdom is reigning today!

The book of Kings picks up roughly where Samuel ends, that is, with David passing the baton on to Solomon, third king of Israel. Not long after, we see Solomon building the glorious and majestic temple, where God Himself would dwell. This catapults us into Israel’s golden age, when she was the envy of all the other nations. Things were going well. Then Solomon, wisest person to ever live, begins to stray from God (wisdom doesn’t guarantee obedience), and things take a turn for the worse. King after king succeeds Solomon, yet almost all of them turned Israel even further away from her covenant and faithful God. Not long after, Judah split off from Israel and formed her own kingdom. God, who keeps His every promise, had to give even His chosen people what their rebellion deserved. In 722BC, the Assyrians conquered Israel, and deported her inhabitants to distant lands. Judah followed suit; in 586BC, the Babylonians invaded and sacked Jerusalem, destroying even the beautiful temple of God. By the end of Kings, God’s chosen people were exiled from the promised land.

The book of Chronicles begins with a lengthy genealogy (making it a rather unpopular book to read), before apparently jumping back in time and covering virtually the exact same time frame that Kings covers! Indeed, much of Chronicles is a straight repetition of Kings, with differences here and there. What on earth is it doing in the bible? This is the key: Kings was written while Israel was in exile (scholars believe), while Chronicles was written post-exile, that is, after they had been restored back to the promised land! Sorry for the spoiler, but yes, God ends up restoring Israel back to the land. Indeed, chronologically, Ezra and Nehemiah (which come right after Chronicles) pick up straight from the return of Israel from her exile.

So what does this mean in terms of reading Kings and Chronicles? Although both accounts cover roughly the same period in history, they are written from different perspectives and for different purposes. Keep in mind that these books were written for Israel’s benefit, and aren’t merely historical records. The book of Kings asks the question “in light of God’s covenant with Abraham (promised land) and David (everlasting kingdom), how did this happen to us?” The answer is not that God failed Israel, but that she failed God by breaking the covenants. Kings teaches clearly that it was Israel’s covenant unfaithfulness that caused her exile.

In contrast, Chronicles retells the same story but with the purpose of exhorting Israel to return to the true worship of Yahweh. Fragmented and fractured from being scattered into pagan nations, Israel needed to be reminded of her special lineage (hence the genealogy, all the way from Adam!) and the central place of worship amongst God’s people (hence the lengthy sections on the Levitical priests and building the temple). For this reason, Chronicles is not concerned with stories such as David’s adulterous affair or even Solomon’s many wives who caused him to stray. It’s not about covering up and rewriting history; it’s about where the focus and purpose of the account lies. Indeed, in many places, Chronicles adds many historical details which Kings omits. Together, they form a rich account of a major period in Israel’s history.

That pretty much answers the first question, which was why those books are in the bible. The second question was why we should read them, and here is my answer:

1. As was the answer to the first question, we should read Samuel, Kings and Chronicles because it covers a major period in Israel’s history! We would be missing so much if we had not these books. They describe and explain how the monarchy (king-ship) in Israel began, the obedience and repentance of king David, the promise God made to establish David’s throne forever, the purpose and construction of God’s temple, the division of Israel and Judah, the succession of kings, and the reason behind the painful exile. Taken as a whole, these books teach us the importance of faithfulness and obedience to God, and points forward to the fulfilment of God’s covenant with David in Jesus, the true Saviour and King.
   
2. Answer two is that we should read Samuel, Kings and Chronicles because it provides the backdrop to virtually the rest of the entire Old Testament. The period that these books span, roughly 1100BC to 500BC, is the same time frame in which the poetry books (Psalms, Proverbs, Song of Songs), major prophets (Isaiah, Jeremiah, Ezekiel) and the minor prophets (all the rest) were written too! In other words, it is within the events covered by Samuel - Chronicles that all these other books were written. I really want to emphasise this now because I’ve found from experience that it’s so easy to lose sight of the context when we reach the prophets like Isaiah and Jeremiah (in a few months). At the risk of oversimplification, almost every prophet had the same message, which was “turn back to God!” Set in the context of the many corrupt kings of Israel and Judah, you can see now why this was such a pertinent message. God spoke so much (not least through Elijah and Elisha, as we saw in Kings) through so many prophets to try and bring His people back to Him, and this makes Israel’s rebellion all the more stark and offensive to God.
   

Here’s a timeline from my bible (TNIV Study Bible) which summarises neatly the time frame that these books cover, and overlays on top of it when each prophet had his ministry. Click to enlarge the picture and keep it for your reference. 

I hope you have a better understanding now of the purpose of the books of Samuel, Kings and Chronicles, and can see why we Christians in the 21st century still need to read them. God had much to teach Israel through those books then, and has lots to teach us through those books still.