We study the Bible with the understanding that it is the only book in existence that contains a communication directly from God. There is something in it for everybody, even an atheist, because it is accepted by everyone, even hardened skeptics, to be historically accurate. Those of us who believe in God's existence, also believe that God is the creator and sustainer (by His natural law) of all that exists, both visible and invisible. We also believe he did not leave us without guidance. So, believing in verse one, that He is the creator, is essential to understanding anything else He has to say. If verse one (" In the beginning God created the heaven and the earth") is false, then all of the Bible is a falsity and totally unreliable. Further if you are of that understanding, that is, that God didnot create the heavens and the earth, you are wasting your time reading this articleand studying the Bible. God has nothing to say to you.
He "has said something about" you...
"...the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness, because what may be known of God is manifest in them, for God has shown it to them. For since the creation of the world His invisible attributes are clearly seen, being understood by the things that are made, even His eternal power and Godhead, so that they are without excuse,..." (Romans 1:18-20)
God originally communicated his will to men directly through the patriarchs; (Adam through Moses) that is, He spoke to them and told them what was expected of them. Then He spoke to them through the Law that was given to Moses and was written down in statutes and ordinances, governing His people, the children of Israel.
They were His people, because everyone else (the Gentiles) had completely rejected Him as they did before God destroyed all men with the flood (all except Noah and his family). God gave the children of Israel laws and "the promised land", which was a figure of a future, spiritual promised land. Contained in these laws was a means of atoning for sin by animal sacrifice. The Law (the old covenant) was to be their tutor, teaching them that God would be their king as long as they obeyed His laws and that some day, a new covenant would be given them, based on better promises.
"...But this is the covenant that I will make with the house of Israel after those days, says the LORD: I will put My law in their minds, and write it on their hearts; and I will be their God, and they shall be My people. No more shall every man teach his neighbor, and every man his brother, saying, 'Know the LORD,' for they all shall know Me, from the least of them to the greatest of them, says the LORD. For I will forgive their iniquity, and their sin I will remember no more." (Jeremiah 31:33-34)
The children of Israel were a rebellious people and turned to worship idols that the Canaanites worshiped. The Canaanites were an evil people, condemned of God, to be dispossessed of their lands by Israel. These were an exceedingly fertile lands. God said it was "the land of milk and honey". God helped Israel to destroy the Canaanites, but Israel wearied of the battles and instead lived and traded with them and even intermarried with them, against God's explicit instructions against all association with them.
God stopped helping Israel when they turned to idolatry and allowed the surrounding nations to enslave them, but God still loved His people and sent prophets to tell them how He would save them if they would come back to Him. When they repented, God sent deliverers to rescue them from their oppressors. These men, who were sent by God to save them, were called Judges (Samson was one of them). There were many judges, because Israel kept returning to idolatry after a period of peace. This happened over and over until Israel demanded an earthly king. Even though they rejected God as their King, He gave them Saul who was their first earthly king. Saul was succeeded by David and then Solomon. Under David and Solomon Israel prospered and became a very great nation, constructing a great temple in Jerusalem.
Then Israel returned to idolatry and split into two kingdoms. God sent against them two Gentile nations, the Assyrians and the Babylonians, who eventually defeated them and brought them home to their nations as slaves. The Medes and the Persians conquered Assyria and Babylonia and after 70 years in captivity, a remnant of them were returned to Jerusalem to rebuild their country. About 430 years later, a man called Jesus began teaching that the New covenant was about to be revealed and the long promised kingdom was about to be established . Unfortunately, the Jews, as they were now called, believed the future kingdom they had long awaited, would be a physical kingdom, restoring the glory of Israel as it was under David and Solomon. Israel was at that time being ruled by Rome and they hated being under their thumb, so this helped establish in the mind of the Jews their expected return to prominence. Jesus would not ride in on a white horse, as a glorious king, defeating Rome and re-establishing Israel. Instead, He was a meek man, preaching that all men should repent and return to obeying God. After unsuccessfully attempting by force to establish Jesus as king, and being unable to refute his teaching, they decide to kill Him.
This brief synopsis, of course leaves out a lot of details, but covers the major high points and provides an overview of much of the Old Testament. Left out was some of the Genesis outline of the creation, the genealogies, the great patriarchs...Adam, Noah, Abraham, Isaac, and Jacob, an account of the flood, slavery in Egypt, The exodus, the giving of the Law at Mt Sinai, the wilderness wanderings, and great men of faith, such as Joshua and Caleb. The Bible records for us the accounts of all these men and their wives and children. It tells of the prophets and gives their records of God's testimonies to Israel. It includes the poetry and sayings of inspired men and so much more that only study and meditation can reveal.
The main reason we study the Old testament today is because it reveals that which God supplied to men leading up to a fulfillment in Christ. It can be said the Old Testament gives us the mind of God and the New Testament, the mind of Christ, but that doesn't touch the hem of the document containing 66 books of what God wants us to know, out of a sea of knowledge. The Bible is a book that can never be captured in the mind of it's readers. There are people who say they can recite the book from cover to cover. What a blessing that would be to have such a memory, but knowing what it says and fully comprehending it, are two entirely different things. I am 70 years old (at the time of this writing) and if God gives me another 20 years or so, I know I can add to my understanding, but I know that only in the hereafter will I gain a perfect understanding of it.