Say you have an Apple computer, iPod, or whatever. You go to a friend’s house, you’re hungry, and your friend pulls an apple out of the refrigerator. I really hope you would never try to listen to music, check e-mail, or anything else with that fruit. You should not only compare apples to apples, you should compare each apple with apples of the same type – fruits to fruits, gadgets to gadgets.
In the same way, you need to not only compare Scripture with Scripture, you need to let God help you to use your mind to understand it.
As an example, “thou shalt” in some places is a warning – in other words, “If you do this, this will definitely happen.” God is all-knowing, so He knows exactly what will happen no matter what choice is made at a given time. At other times, “thou shalt” is a command. By studying the verse, the verses around it, the book, and what else you know about God’s attributes (love, mercy, justice, etc.), among other things within Scripture, you can figure out which is which.
Take Ephesians 5:18, for instance. It is written to believers at Ephesus. It’s easy to see that the audience is believers. We can easily say the command is for us; part of how to live a Godly life. It is part of a chapter on living Godly lives. The first part, telling people not to be drunk, is easy. The word “but” means to do something else instead, and is referring back to the first part. The total control of the Spirit over a person is what we should have, instead of the excess, mockery, etc., of drinking.
Other times, believers are said to be filled with the Spirit the moment they get saved. Jesus promises the Comforter, which is the Holy Spirit, will be in all believers. So, since “filled with the Spirit” in Ephesians 5:18 is a command to believers, it can’t meant he same kind of filled. That “filled” happened when you trust Christ as Svior, and stays with you. The “filled” in Ephesians 5:18 means a continual control by the Spirit, so that God’s love, mercy, and so on just pours out of us. We saw that without reading one word of Greek! Some verses are harder, but it’s rather easy when you put your mind to it.
However, the devil tries to complicate things. This is why it’s important to read consistently, and vital to do as Psalms 119:11 says – hide God’s word in your heart. That means, keep it and protect it.