Recovering the Foundational Doctrines
If you talk about a doctrine that needs to be recovered, you have to start with the doctrine of Scripture. Because once you’ve discovered the doctrine of Scripture, and you’ve nailed it down, and you believe it as the Bible declares it, you now are on safe ground to pursue other doctrine. The doctrine of Scripture is the most import doctrine.
The Bible defends itself from itself—in other words, the Bible is its own defense. I think it’s clear to anybody who studies the Bible, certainly as long as I’ve studied it, that there is a glory and a power, a supernatural character, in the text itself. As you study the text of Scripture, it yields that glory, it yields that supernatural character. So if you have the confidence that you’re reading the Word of God, then you’re on safe ground to pursue any other doctrine.
The second doctrine to be recovered would be the doctrine of God. Understanding the true and living God as the triune God—Father, Son, and Holy Spirit and all the characteristics that are true of them.
The third doctrine is the doctrine of salvation. We have to believe that God is the rewarder of those who diligently seek him. We have to believe in the person of Jesus Christ, the second member of the Trinity, the work of the Holy Spirit, and then the gospel of grace—salvation by grace through faith alone.
Those are the foundation of all other doctrines and you go from there.
How can one know which concepts about Satan and demons are biblically accurate and which are not?
If you're going to enter the ministry, whether as a missionary or a pastor, you will spend the rest of your life (if you're faithful) teaching sound doctrine.
John MacArthur discusses the historicity and significance of Adam in the Bible.