Think about the prophecy of the Virgin Birth. In Isaiah 7, the enemies of Israel have plotted against her, but God prophesies that by the time Isaiah gets married and has a kid and the kid is a few years old, the enemies will have been destroyed. Here's the text of verses 14-16:
Therefore, the Lord Himself will give you a sign: The virgin will conceive, have a son, and name him Immanuel. By the time he learns to reject what is bad and choose what is good, he will be eating butter and honey. For before the boy knows to reject what is bad and choose what is good, the land of the two kings you dread will be abandoned.For hundreds of years, readers of the Bible understood this to be a prophecy which was fulfilled in Isaiah's son.
But then, Yahshua (Jesus) was born of the virgin, Mary (Luke 2:26ff):
In the sixth month, the angel Gabriel was sent by God to a town in Galilee called Nazareth, to a virgin engaged to a man named Joseph, of the house of David. The virgin's name was Mary.and suddenly this prophecy took on a new meaning, as explained by Matthew in Matt 1:20-25:
Now all this took place to fulfill what was spoken by the Lord through the prophet: See, the virgin will become pregnant and give birth to a son ....As far as humans were concerned, the meaning of the text changed: for hundreds of years it only referred to Isaiah's wife and son; now, it also refers to Mary and Yahshua.
This idea of "dual fulfillment" of prophecy is well-accepted by many Bible scholars, but what seems amazing to me about it is that it sometimes means that the text has changed its meaning, when viewed from a human standpoint. It might be argued that God had always intended both meanings, but from a human viewpoint, the text changed meaning after the second fulfillment gave it the new meaning.
This is not the only example we have of the Scriptures not having a fixed meaning. In Zechariah 11, Zechariah is paid low wages of 30 pieces of silver, and God tells him to "throw it to the potter". I doubt very seriously that anyone reading that passage took any other meaning from that passage until Judas threw away his payment of 30 silver pieces for betraying Yahshua (Matt 27:3-10).
These are inspired examples of the meaning of a text not being fixed. But the process still goes on within the church, perhaps by the Holy Spirit's leading. For example, Isaiah 62:2 prophesies that the nation of Israel will inherit a new name. The immediate fulfillment, and probably the only meaning taken from this passage for hundreds of years, is that God was using a poetic means to tell the nation that it would no longer be called "Deserted" or "Desolate", but rather "I delight in Her" and "Married" (62:4). But thousands of years later, the church often points to this promise of a "new name", and sees Acts 11:26 as the fulfillment of that promise, in which "the disciples were first called Christians in Antioch". To these Christians, the meaning of Isaiah 62:2 has changed from the black-and-white meaning given in 62:4, to that given in Acts 11:26.
The conclusion is that the meaning of the Scripture to humans has not remained fixed: it has changed, and in at least some cases (two of the above three examples), by inspiration.
What does this mean? I don't know. I just find it interesting.