The US constitution is not the only text whose interpretation has changed throughout history. The Bible has even more than the constitution been interpreted and reinterpreted throughout history. Sometimes to the point that the original meaning is lost or forgotten in the haze of history. Knowing that this happens is the first step towards a fuller and richer understanding of the scriptures. To illustrate this I will consider how we interpret Psalm 72.
In the LDS version of the Bible the chapter heading for Psalm 72 reads:
David speaks of Solomon, who is made a type of the Messiah—He will have dominion—His name will endure forever—All nations will call him blessed—The whole earth will be filled with the glory of the Lord.
For the most part this is an accurate summary of the psalm but the summary explicitly draws a link between Solomon and the Messiah. But if we read the text of the psalm and just consider the text itself there is absolutely nothing in it that makes this connection. There is no explanatory or parenthetical text that explicitly states that the purpose of the psalm is to create an archetype of the Messiah. Just considering the text, all we can surmise is that King David was extolling the virtues and glory of his son Solomon. By itself there is nothing to suggest that David was speaking of Solomon as "a type of the Messiah".
We also have no statement from David explaining that he intended the psalm to be interpreted as referring to the coming Messiah. So where did we get the idea that the purpose of the psalm was to describe the Kingship of the future Messiah?
When I started considering this question I wondered if this was peculiar LDS interpretation of the Bible or if it had a broader acceptance. As I looked up different commentaries of Psalm 72 I noticed that about half mentioned that particular interpretation. So this idea is not limited to the LDS world. The more I looked into it I could tell that the idea had been around for quite some time. But still I was interested in where it had originated.
I looked into Jewish commentaries on Psalm 72 and discovered that Jewish scholars of the 15th and 16th centuries wrote extensively about the coming "King Messiah" as described in Psalm 72. These scholars took their cue from medieval Jewish scholars of the 11th and 12th centuries, who in turn took their interpretations from earlier commentaries. The idea can be traced back to the 1st century BC with the first written version of the Targum, which was a series of spoken explanations given by a Rabbi to help people who didn't know Hebrew to understand the scriptures. Beyond that the source of this interpretation comes from the oral commentary passed down from one Rabbi to another. Thus we can only place the origin of this idea sometime before the 1st century BC.
So while the idea that Psalm 72 "was designed to refer ultimately to the Messiah" is over 2000 years old, we have absolutely no evidence that King David intended that psalm to be interpreted in that way. It is possible that he did intend it that way, but then again it is entirely possible that he was writing a psalm for the future coronation of King Solomon, and nothing more. I should point out that even though this interpretation has a long history, it is by no means universally accepted. It's not that some commentators reject it, they just never mention it, or only mention it in passing. It is treated as one of a number of possible interpretations.
So while the LDS chapter heading states, "David speaks of Solomon, who is made a type of the Messiah" there is nothing in the text to suggest that the original purpose was to make "a type of the Messiah". It is entirely possible that the psalm was written solely for King Solomon and later generations used it to describe the coming King Messiah, as many scholars now do.
When we read the scriptures we should keep in mind that our interpretation of certain passages may be different from the original intent. This is not to say later interpretations are wrong, but we should be careful not to impose a particular interpretation on the original authors that they may have never intended. When we remember this we can begin to have a fuller understanding of the scriptures and how we read and interpret them.