Dating the Bible - Wikipedia
Scroll down to table IV.
Left side dates are speculation as to when the original texts MAY have been authored, but nobody knows for sure since there are no original texts in existence. We haven't even found copies written in Hebrew or Aramaic.
The far right side dates are the earliest known papyri, which range from 125 - 400 years AFTER Jesus.
What most people don't stop to consider is the sheer amount of time between the speculative dates and the earliest known papyrus for each book. All of those far right side dates are what all NT's are founded on.
Every single word in the NT is a Greek copy of another copy of unknown origin, written by an unidentified copywriter....hundreds of years later.
There's a fragment of John that's the earliest known at 125 - 160CE.
Taking all of this into consideration, we have no idea just how many copies exist, who wrote them or even how accurate they are to the original texts...none of which have ever been found.
Let's face it, these weren't trained Sofer...they were everyday normal people copying these texts and it's why there are so many contradictions found in the NT.
I'm not saying that the entire NT is inaccurate, but corroborating texts are absolutely needed not only to support their validity but also to support their accuracy.
And if anyone is making the claim of "Jesus said" publicly, then that passage had better be coming from one of Jesus 12 apostles and was actually an eyewitness of the event.
Not doing so would be irresponsible.