There are two New Testament scripture verses that give us the first principles for understanding the Old Testament. In 2 Timothy 3:16-17, it is written, "All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the servant of God may be thoroughly equipped for every good work."
In this section, Paul teaches us that the Old Testament (Scripture) comes from the breath (spirit) of God and has a purpose: Righteous living.
This is the first principle: There is only one correct interpretation of any passage of scripture. The meaning intended by the Spirit is the one correct meaning for any passage.
This principle is reinforced by the Apostle Peter: "Above all, you must understand that no prophecy of Scripture came about by the prophet’s own interpretation of things." 2 Peter 1:20. In suggesting that there are private interpretations, Peter is also intimating the important role of the Church in Biblical interpretation. For example, if you have an insight into the meaning of a text, but no other Christian has seen this possibility in the two millennia of New Testament Church history, you may want to re-examine your results.
Two other principles from the New Testament that help us understand the Old Testament are found in Mark 4:33-34 (With many such parables Jesus spoke the word to them, to the extent that they could understand. He did not say anything to them without a parable. But privately He explained all things to His own disciples.) and 1 Corinthians 10:11 (These things happened to them as examples and were written down as warnings for us, on whom the culmination of the ages has come.)
The text of the New Testament is saying that heavenly things are inscrutable, so God teaches us spiritual things in parabolic, human terms.
Now that Jesus has come and fully revealed God to humans as an human, then we can know God as much as a natural human being has the capacity to know spiritual things.
This is the guiding principle for my study and interpretation of the Old Testament. Human events teach us about God. That is what you are intended to see. (Of course, the events also teach us about sinful man.)
