Jesus said, "I am the way and the truth and the life." John 14:6
Jesus also spoke, "But when he, the Spirit of truth comes, he will guide you into all truth." John 16:13
"Whoever invokes a blessing will do so by the God of truth." Isaiah 65:16
Jesus is the truth, the Holy Spirit is truth, God is the truth and the Bible which is God's word, is the truth.
"The truth will set you free." John 8:32
The truth sanctifies and frees us. It straightens and strengthens us. The more truth is embedded in us, the stronger we are in faith, and the less we are swayed and shocked by the world and Satan. The truth is strong. Honesty, truth, integrity and straightness go together. The truth makes us more godly.
"Whatever is true...think about such things." Philippians 4:8
The Bible encourages us to think about truthful things. Things like the Bible, God the Father, Jesus, and the Holy Spirit. And anything else He wants to show us.
Jesus said of the devil, "He was a murderer from the beginning, not holding to the truth, for there is no truth in him. When he lies he speaks his native language, for he is a liar and the father of lies." John 8:44
Satan is a liar. Lies, deception, trickery and evil have a common root. There is no good in Satan, and no truth. Staying close to God keeps us from becoming worldly. It's crucial to test the spirits to make sure that we are following the truth, and not something that appears truthful but is a lie.