First, we must have a frame of reference. We cannot compare what someone has written or spoken unless we have a standard by which to evaluate it. For the Christian, our foundation is no less than the Word of God in its entirety. It is the truth written for our instruction. As 2 Timothy 3:16 tells us: "All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness...." Because God is the author who is immutable (unchanging), holy, and righteous, we can trust what is written in the pages of the Bible. The Reformers found this to be the center of their complaint against Rome. They held that this is the only rule for life and faith not Papal authority or tradition. Therefore, we need to weigh anything we read, hear or see according to the truths contained in God's Word.
In His high priestly prayer for the disciples, Jesus said in John 17:17: "Sanctify them in the truth; your word is truth." Jesus came not to abolish the Law and the Prophets but to fulfill it. With this in mind, we can rest knowing that we have the best resource at our fingertips. Unfortunately, many believers fail to dig into the Word of God on a regular basis. This leaves them vulnerable to every "wind of doctrine" that comes along including the ideas of "popular" authors or speakers. We have been warned repeatedly to be on guard, and we have the example of the Bereans in the book of Acts 17:11 which says: "Now these Jews were more noble than those in Thessalonica; they received the Word with all eagerness, examining the Scriptures daily to see if these things were so." Even though it was the Apostle Paul, himself, and Silas that came preaching to them, they still took the time and effort to check Scripture to see if what they were saying was correct. This is an important example of how we need to take our faith seriously so as not to be misled.
At this time in our history, there are many ideas swirling around in our culture: homosexual marriage, the emergent church, goddess worship, and other "New Age" concepts. How will we be able to keep our balance unless we are grounded in the Bible? We need to know what we believe and why we believe it. As Acts 20:27 reminds us, we must be able to know and share the "whole counsel of God" as revealed in both the Old and New Testament.
Our weakness in this time is the tendency to be drawn by celebrity preachers, mega churches, contemporary styles that eclipse the true meaning of worship, and feel good books/messages. Let us, therefore, be proactive and take the time to examine books, sermons, and activities to make certain they line up with God's Word. If they do not, we must put them aside in favor of the Bible. May God help us to be faithful! Selah!