Mattew Henry says that since there is a lot of repetition of what had already been said in other books of the Bible that if there were parts of the Bible that could be excluded, they would be it, and yet there are things that are not found anywhere else. I simply accept the fact that God preserved them for us and therefore we need to read and learn what we cab from them which starts with 1st Chronicles. He also points out that the second and third books of the New Testament have a lot of duplication, and we still learn a little more from each of them. All of God's word is important, even if we may think it repetitious.
He also points out that people didn't always have the whole Bible read from, so these Chronicles might have been what they had. All I know for sure is that it is a part of the bible, so we need to read all of it and look for what God has to tell us. Matthew Henry also says that Ezra was supposed to have penned these books as a scribe of the Law of the Lord. These books are called the words of days in Hebrew, according to Matthew Henry. There are many genealogies, and the calling of those whose genealogies are given, and there are some things that are not found anywhere else, including the priests, both Aaronic and Levitical priesthood. There is also the story of David the settlement David made of the ecclesiastical affairs and the preparation he made for the building of the temple that are not found elsewhere. There are stories of the reigns of kings and dates of kingdoms, as well as the lives of common people who were doing the work of God. So, we learn that God was and is at work in the world and that He works in the lives of both Christian leaders and laymen as we do His work. Of course, it is always best if the worldly leaders are following God as well.
We have the story of the Philistines fighting against Israel, and Saul their first king and God choosing David to rule in Saul's place. Then, we are told of Saul's death by his own hand because he was afraid to fall into the hands of his enemies. The Philistines then took hishead and his armor to show their power. If we remain true to God, we never have to be concerned about being spiritually defeated, and had Saul remained true to God, he wouldn't have either. We can also be certain that many times people of the world will do all that they can to dishonor Christians.
Then the men of Jabesh Gilead took back Sauls's body and buried it and fasted seven days. These men were brave in doing this, since the Philistines were still about. We must do what is right in God's eyes even if it brings us danger in the world.
There is a lot written about David's reign as King, and he was called a man after God's own heart, even though he often allowed himself to give into temptation. We need to be people after God's own heart, and still, we will sometimes fail to live by faith and allow sin to slip into our life, but we will never stop being God's people if we have accepted Jesus Christ as our personal Savior and Lord.