Scripture reassures that God's Word will be a "lamp to my feet and a light to my path" (Psalm 119:105 ESV). When the Bible is our great treasure and constant meditation, then our minds are renewed with wisdom and understanding, (we will become wiser than our teachers) and the Lord will providentially directs our steps (Proverbs 3).
The Bible is that “prophetic word more fully confirmed” (2 Peter 1:19) and the apostle says we would do well to pay attention to it rather than an unconfirmed voice. We will find in Scripture everything we need for life and godliness.
The Lord is too gracious and kind to leave us hanging. So “tell the next generation that this is God, our God forever and ever. He will guide us forever” (Psalm 48:14 ESV). His guidance is clear and sure, revealed to us through the pages of the Bible. It is external to us. And it thunders.