Narrow Our Belief in Truth to Salvation

Believe in the truth
"What is truth?" said Pilate. After he had said this, he went out to the Jews again and told them, "I find no grounds for charging him. (John 18:38 CSB)
They perish because they refused to love the truth and so be saved. (2 Thessalonians 2:10b NIV)
It is good to believe in the truth. It is bad to deny the truth. But truth is so wide that no one can know all truth and no one will believe all truth. So we must narrow it to the most important and most basic truth of all, God's Word. We also must learn to verify truth. Otherwise, how can we prove the God's Word is true?

Believe in God's Word
The entirety of your word is truth, each of your righteous judgments endures forever. (Psalm 119:160 CSB)
Salvation lies in the truth, the particular set of truth - God's Word.

Believe that Jesus Christ has died for my sin
I passed on to you what was most important and what had also been passed on to me. Christ died for our sins, just as the Scriptures said. (1 Corinthians 15:3 NLT)