The Bible is divided into two sections - the Old Testament and the New Testament. As a side note, testament/testimony (depending on the translation) and covenant are interchangeably used in the Bible (see Ex. 34:28-29 as an example), so it seems the Bible is divided into the old covenant and the new covenant - more on that later. Adventists rely heavily on the Old Testament for support of certain doctrines such as required Sabbath-keeping, tithing, unclean meats, and even the state of the dead. Often they will ignore or gloss over passages in the New Testament that clearly teach the opposite viewpoint.
So, where do we go to find instruction for Christians? The Bible says that, "All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness" (2 Tim. 3:16). That being said, there are certain passages that by nature require more weight when it comes to our beliefs. For example, passages that specifically deal with teaching on a topic should be considered first, and more weight should be put on teaching passages than apocolyptic or poetic passages.
One specific example of this being misused in Adventism is on the topic of what happens when we die. One of the "proof texts" used in Adventism to support the idea of soul sleep is Ecc. 9:5 (generally only the first half of the text, too) - "For the living know that they shall die: but the dead know not any thing". Not only is the passage taken out of context (I'll deal with that in another blog), but the passages in the NT dealing with what happens when you die are ignored. I've never been to an Adventist funeral where they mentioned 2 Cor. 5:1-10, Phil. 1:20-26, 1 Thess. 4:13-18 (they use the last few verses but not the first which give a different picture), 2 Pet. 1:13-15, etc. There are entire passages on the subject that go unmentioned because they don't "fit" with soul sleep.
Is that how we should study the Bible? Focusing only on the parts that "fit" with our belief system while ignoring the rest? I personally put more weight on the New Testament in determining Christian beliefs. The Old Testament pointed to Jesus. Once Jesus came, we no longer need the shadows - we have the real deal. That's not to say we can't learn anything from the OT, but we should read the OT through the eyes of the NT (in which it is fulfilled).
We also need to read things in context. That was one thing that I heard again and again in Adventism - Other people take things out of context, but we don't. Imagine my suprise when I found instance after instance of verses (or even partial verses) taken out of context to prove an Adventist doctrine. Do people really not see that, or do they believe the end justifies the means?
Last but not least, we need to try to understand what the author is really saying in the passage. I found this in an article that describes it well -
"Our goal must be exegesis (drawing the meaning out of the text) and not eisogesis (superimposing a meaning onto the text. By using eisogesis instead of exegesis, a Marxist interpreter could, for example, so skew the meaning of the U.S. Constitution that it came out reading like a socialistic document. Cultists have done the same type of thing with Holy Scripture. They so skew the meaning of the biblical text that it comes out saying something entirely different than what was intended by the author."