When a Christian student is honest at examination time even when he has opportunities to cheat, others will feel the impact of his witness. When a Christian family is truthful with the neighbors about the damage their dog did to the neighbor's flower garden, or when the twelve year old boy in the family is honest about the window he broke when nobody was home to see him, then those neighbors will begin to listen to a testimony about a God of truth whose message of truth can bring the assurance of everlasting life. Living in the knowledge of God's absolute truth has other far-reaching implications for our lives as well, such as bowing to His authority over us. If everything God says in His Word is absolutely true, then we are responsible to act on the basis of it, to do what He tells us to do. Something that is true requires that we heed it.
Truth demands compliance.
Many of us resist that. We live in an age of rebellion against authority. Some of us reserve the right to live as we please and seek our own happiness anywhere we think we can find it. But a true God whose Word is truth demands our total submission and faithful obedience. That may sound oppressive and burdensome but, on the contrary, it is the only way our lives can operate smoothly and effectively.