You're probably thinking of Hebrews 4:12, which tells us that God's Word is still at work in people's lives: "For the word of God is living and active. Sharper than any double-edged sword, it penetrates even to dividing soul and spirit ... it judges the thoughts and attitudes of the heart."
In other words, the Bible isn't a dead book, or just something that was written thousands of years ago and then forgotten. The Bible is God's Word, and it is just as relevant and life-changing today as it was when it first came into being. God gave it to us, and when His Spirit applies it to our hearts, God uses it to convict us of our sin and point us to His truth. The psalmist rightly said, "Your word is a lamp to my feet and a light for my path" (Psalm 119:105).
Furthermore, the Bible is complete—because Christ's work for our salvation is complete. By His death and resurrection, Christ fully purchased our salvation. We don't need to look for another Savior; in Christ alone "are hidden all the treasures of wisdom and knowledge" (Colossians 2:3).
My prayer is that you will discover the Bible for yourself—and not only the Bible, but also the One who is at its center: Jesus Christ. God's Word tells us everything we need to know for our salvation—and when we know Christ, our salvation is secure.