The questioner had a large list of verses to demonstrate that David’s reign was well over 40 years. That said, only one of the verses supplied would necessitate a reign of over 40 years. That single verse is 2 Samuel 15:7. It reads:
Now it came to pass after forty years that Absalom said to the king, ‘Please, let me go to Hebron and pay the vow which I made to the LORD.’ (2 Samuel 15:7)
It is generally accepted that this should read four (Heb. ebra), not forty (Heb. myebra). There are some manuscripts which read four years (the Syriac & Arabic texts). In the writing of Josephus, this is said to be four years as well, not forty. The issues enters our English translations from the Masoretic text, which appears to have a copyist error in it.
We have noted in the past the possibility of and existence of copyist errors. As we’ve noted before, if such were found in any other ancient document, folks would pay no attention to it. And yet the number of copying errors and nature of those errors is few and insignificant. And, in some cases, like this, we have other ancient manuscripts to help verify what the text should read.
There is a copyist error, but there is no contradiction.
A response to 1001 Bible Contradictions.