Our question is Has God revealed the truth of the age of the earth?
The two ways God has revealed truth is through His Word, and His world. So let us first look at what the Word of God says about the age of the earth, and whether the question is addressed. If we can come to a satisfactory conclusion about the position of theology on the question, then we can look at what science has to say.
The obvious place to begin is Genesis. Gen 1:1 simply says that, In the beginning, God created the heavens and the earth. No indication of age there.
Gen 1:2-5 continues:
“The earth was without form and void, and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters. And God said, “Let there be light,” and there was light. And God saw that the light was good. And God separated the light from the darkness. God called the light Day, and the darkness he called Night. And there was evening and there was morning, the first day.”
And the rest of Gen 1 continues with the events of the remaining six days of creation, utilizing the same language (i.e., there was evening and there was morning, the nth day). Then Gen 2 and 3 tells the history of man in the Garden and his Fall, his expulsion from the Garden, and Genesis continues with the history of the ancient world. Nowhere is it said, “The age of the earth is x.” So how can we know?
If we remove the chapter and verse numbers, headings, and so on, and just read the Genesis history as it was written, it reads as if it is a sequential narrative of events. Since Adam was created on the sixth day, and his age is given, along with the age of his descendants through the patriarchs, the years can be added up, to the birth of Jesus (for His genealogy to Adam is also given); and thus before the advent of modern science, the Church has traditionally assumed a young age of the earth, just based on the plain reading of Scripture.
Moreover, many Biblical scholars before the modern era made the issue of biblical chronology their life- long study, and were classical scholars of the first rank. Since they did not have archaeology to draw upon, they instead drew upon the writings of the ancient world. In researching The Story of the Ancient World, I can attest that the amount and number of these writings is vast, which was at first a surprise, because we are led to believe that the men of the ancient world left little account of themselves.
The ancient histories left by non- Christian and non- Jewish sources (Babylonia, China, India, etc.) also all record an earth which is thousands, not millions, of years old. Therefore before the modern era, it was the unanimous consensus of both Catholic and Protestant, that the earth was young, just based on an appeal to theology, not having science at that point.
Of course, saying that the men of old all believed the earth to be young based on a plain reading of Scripture and a study of the writings of the ancient world, even of non- Christian sources, does not answer all the objections, but it does serve to show us that the age of the earth controversy, as far as theology is concerned, is a modern one, since the advent of modern science.