When I got to Chronicles I realized most of it was a retelling of Judges and Kings. I was curious as to why it would be included in the Bible and what its purpose is…

“First of all, not all of the content of the Chronicles is found in Samuel and Kings. In fact, over half of the content of Chronicles is unique.”  https://www.gotquestions.org/purpose-of-Chronicles.html

“Also interesting is the name of 1 and 2 Chronicles in the  Septuagint  (a Greek translation of the Old Testament produced around 300 BC). The title translates as “The Books of Things Left Out,” referring to additional details surrounding the historical events recorded in the books of Samuel and Kings. Due to the Judean emphasis of the Chronicles, we learn much more about the southern kingdom of Judah and its kings; the books of Kings contain more detail about the northern kingdom of Israel. “

Another site also has some interesting statements, here is a snippet of what they said:http://info.austingrad.edu/christianstudies/things-omitted-why-chronicles-is-important

“Many Christians through the ages have looked at it as an addendum or appendix, with some helpful additions, but paling in importance next to the magisterial history of Samuel and Kings. 

This widespread opinion does not do justice to the importance and influence of Chronicles. First, the theology and purpose of Chronicles is completely different from Samuel and Kings. Samuel and Kings are part of a much longer history, from Joshua to 2 Kings, with Deuteronomy as the introduction. The purpose of this collection is to hold Israel up to the light of the law in Deuteronomy and show how the people have consistently violated the covenant, especially the laws against idolatry. After hundreds of years of warnings given by the prophets, this history shows the inevitable consequence of idolatry —loss of land and exile— as spelled out in Deuteronomy. There is however, hope for Israel. If Israel will repent and return to the Lord, as she had done so often in the past (the period of the Judges, David, Hezekiah, etc.), God would once again hear them and restore them. “