Prove it.<quoted text>
By the time the gospels were written most of the apostles and disciples were dead and could not be witnesses to anything.
You cannot prove that!
We know that some of the books were written by different people but many of the writings are attributed to Disciple Paul.
BTW: GODS Holy Spirit wrote the Books.
2 Timothy 3:16-17
16 All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, 17 so that the servant of God may be thoroughly equipped for every good work.