"Truth" is an important Bible word, being found 189 times in the Old and New Testaments. It is an important Bible word because of what it is. Many have walked in old Pilate's shoes, asking, "What is truth?" (John 18:38). Jesus' prayer concisely answered that question, even before Pilate uttered it. The Lord said that God's Word is truth (John 17:17). Yet, we can easily find ourselves substituting that for something or someone else. Notice the following.
The culture cannot be the standard of truth. Not only does their standard constantly change, its basis for what is considered truth is skewed and self-determined. In other words, a worldly approach to "truth" more often than not coincidentally coincides with what people want to do. Many times, the world gets it exactly backward. As Isaiah put it, the world using its own wisdom calls evil good and good evil (5:20). By its own standards, the world does not come to even know God (1 Cor. 1:21). 1 John 2:16 thoroughly dismisses the idea of one's worldly contemporaries being the standard of truth.
The religious world cannot be the standard of truth. In far too many areas, individual religious groups, denominations, have invented their own doctrines. They, too, can form their teaching and convictions based upon the strong pressures of culture. They can reform and reshape their beliefs to accommodate people's circumstances. For any number of reasons, the religious world veers left or right of biblical center (cf. Deut. 5:32; Prov. 4:27).
The Lord's church cannot be the standard of truth. Opinions, traditions or customs, and preferences cannot be passed off as synonymous with or equal to truth. A congregation of God's people, well-intended or not, can depart from the truth. We cannot blindly follow even these away from truth.
A particular school, preacher, periodical, etc., cannot be the standard of truth. We can admire colleges and training schools for their work, teachers, and graduates, but this confidence must always remain conditional. As we remember that one can veer from truth by binding or loosing, we must always measure what is promoted as truth with God's divine standard. What is true of institutions is equally true of individuals. Even if someone speaks passionately, with conviction, and without hesitation or reservation, our job is to compare their message with God's (cf. Acts 17:11). We can easily confuse charisma and chemistry with truth, but there is no inherent connection.
You and I cannot be the standard of truth. All of us have scruples, consciences, preferences, proclivities, likes, and dislikes. We may feel quite strongly about them. But, we cannot make ourselves the standard of truth on any biblical matter.
There is but one right standard and that is scripture. Yes, there is the matter of proper interpretation and recognizing there can be improper interpretation. On some matters, scripture may not be as definitive as we want or even initially think. Yet, regarding anything that would effect our salvation, God has a clear, understandable "position" stated forth in Scripture (cf. 2 Pet. 1:3). What He says on the matter is the truth, the whole truth, and nothing but the truth. Accept no substitutes for this!