1) The Bible is not a single text, but a collection of over 60 books authored by more than 40 writers. Hen you read through it you will find a unity of doctrine and theology. Yet most of the writers never meet or read the works of any of the others, And yet they all record the same ideas about the same God who they claimed appeared to them and taught them those things. But 40 people in a room (even 40 Christians), ask a theological question and see how many dozen different opinions you get. And yet the Bible somehow has a consistent theology throughout it. Not humanly possible.
2) If you read through the Bible you will find people (who never meet and never read each others works) having the same visions, using the images, etc. While it might be possible for one person to have a hallucination and write about, you will not find 40 people who had such vision across 1800 years that are all the same. That is not humanly possible.
3) If you read the Bible you will find that it has many prophecies within it that are fulfilled historically outside of the text of the Bible. Many of them after the time the Bible was completed. For example, we have copies of the writings of the prophet Daniel in the Dead Sea Scrolls that we know were made between 250 and 150 BC. (The actual text itself dates from around 500 BC but none that old survive.) In the book it gives a brief history of the Medes, Persian, Greek, Roman, Byzantine, Holy Roman empires and the European Union. They cover the major empires of that region of the world from 500 BC into the 21st century. And yet this was written during the Medes empire. And the copies we have are from the time of the early Greek Empire. Again, not humanly possible. And that is only one of hundreds of such prophecies.
4) Sir Ramsey Clarke is considered to be the father of archaeology, developed most of the techniques used today, and was knighted for his accomplishments in the field. He was also an outspoken atheist who went into the field, and turned it from "grave robbing" into an actual science, in order to prove that the Bible was wrong. After 40 years in the field, he had to write that he was unable to disprove a single thing in the Bible. Rather he had to conclude that "Luke" (who authored the gospel by the name and the book of Acts) was the finest historian who had ever lived. He proved the Bible to be true.
Just to list a handful of reasons that we know the Bible is true.