Christians experience spiritual warfare over “Truth” — since the start of the church. As the church continues to lose this battle, the meaning of truth changes with the surrounding culture. Why? We don’t like to appear combative. Ask the Pharisees, Jesus was controversial and had no problem with challenging the Pharisees in public. God created the universe and everything in it. It makes sense that He is Truth. We are to avoid allowing the culture to define our idea of right and wrong. Instead, we are to mature in Christ. The Bible warns us to avoid the following behaviors:
1) Infantile (1 Cor. 3:1–4),
2) allowing others to dictate reality (Luke 8:24; James 1:6),
3) allowing the culture to dictate reality (Luke 20:23; 1 Cor. 3:19; 2 Cor. 4:2; 11:3).
When a person does not grow spiritually, they are stagnant. They assume they have learned enough. The result is that they become vulnerable to filling in the blanks with other ideas that conflict with the truth (1). We all have friends. The problem is when we let them dictate reality. If we stop and seek God’s wisdom, different facts come forward (2) The third is related to the first. The process of being deceived can happen at any level of maturity.
We now have groups, such as Millennials and later, who have never been to church, nor has Jesus been discussed with any frequency in the home. When they visit a church, their preconceived idea of justice, righteousness, right, and wrong, etc. come from schools and universities, not the Bible. For Baby Boomers, going to church Sunday was something one did. At the least, we heard preaching every week. The cultural landscape is continually changing, something Satan initiates, while the church should be rock solid on truth.
In your culture, it may be you live where another religion dominates, or perhaps the government acts like a religion. It’s possible they are bullies and don’t want Christianity around them. Do you back off your beliefs? Christians have the truth on their side and should not back down.
Satan, of course, attacks the concept of Biblical truth by promoting the idea that the Book is not God-inspired. Once that is achieved, the Bible becomes irrelevant. School systems and universities ridicule the Bible. It’s no wonder the idea of absolute truth is a hard concept to grasp. Denominations do the same thing when church doctrine supersedes the Bible. The church has not suitably defended the notion of truth and suffered the consequences for centuries. Instead, the church attempts to be hip and fresh so that the building matches the expectations of the surrounding society. Some churches don’t change anything. The result is a 50-year time warp when visitors walk in the building. What folks need to see when they enter a church is people practicing what they preach and always searching for the truth.
In some cases, the church refuses to take a stand on controversial issues. These subjects are labeled “too hard to understand” and omitted from teaching. I interviewed with a church whose denomination eliminated their position on the Tribulation. Whatever the pastor believes is OK with the church hierarchy. When we avoid the subjects that have controversy, they ignore the question and never even teach the material. Including the truth as one of those subject spells disaster for that church.
Five key passages when studying the concept of truth.
1. Ps. 86:11 — Verse 8 talks about God as being alone among other gods. No human institution can measure up when compared to the Lord. The Lord performs works that no other spiritual or physical being can match. Given this truth, David wants to live by God’s truth and is willing to be its student.
2. Isa. 59:14–15 — This passage is a warning for people of any age. When justice nowhere to be found, chaos prevails. When absolute truth is gone, people stumble around like drunks. Lack of reality is what prevails now and will worsen as the Tribulation approaches. The worst part is the reaction from the Lord — He is offended. 
3. Jn. 14:6 — If any doubt about absolute truth, this passage debunks that idea. Given that Jesus is the truth. Given that the Father and Son are one. Then we can deduce that God is the truth and found reliable. The reality we need to know is in the Bible.
4. Jn. 18:37–28 -Jesus came to the earth to testify about the truth (Ps 119:142; 2Th 2:10). People who want to know the truth will follow Jesus in preparation for eternal life.  Those who are outside are not sure what is the truth. Pilate had this issue as do people today.
5. 1 Ti. 2:3–4 — The salvation of ALL humanity is the point here (Jn. 14:6, 17). The passage point to knowledge of the truth as the result of salvation.
Truth is something we should protect! How is the idea of Truth used:
• As a noun indicating conformity to reality or actuality. Something on which we can depend.
• Another noun usage. Anything historical or supernatural is reliable.
• The good news about Jesus Christ is the truth.
• Statements made are considered reliable.
• It is also used at an adjective to characterize something as reliable.