"...and to make all men see what is the fellowship of the MYSTERY, which from THE BEGINNING OF THE WORLD hath been HID IN GOD who created all things by Jesus Christ". (Eph. 3:9).
"Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the MYSTERY which was KEPT SECRET SINCE THE WORLD BEGAN, but now is made manifest.."(Romans 16:25).
think about this for a moment. Our present Dispensation of the Grace of God was a mystery, kept secret since the world began. That goes past Abraham, past Abram, past Adam, to the when the world began. This is so interesting on so many levels. And I think there is enough scripture available to us to at least understand WHY.
The secret things belong to the LORD our God, but the things revealed belong to us and to our sons forever, that we may observe all the words of this law. (Deuteronomy 29:29)
God has told us what we need to know to obtain salvation, live healthy lives with His blessings, what we need to know about His return, and how to have a personal, fulfilling relationship with Him.
There are some things He gives clues about in Scripture, and some things He keeps secret and solely to Himself.
I think that what went on before He created this present age is one of those things He keeps to Himself.