Why was this mystery hidden from the beginning of the world, and where was it hidden?
Scripture says this mystery, or secret, was hidden from the beginning of the world because hiding is God’s prerogative; He is the everlasting God who is capable of hiding things. It was hidden in God, the same God who created all things by Jesus the Christ.
Les explains that Paul’s goal was to make all see the fellowship of this mystery, or secret, which from the beginning of the world or age had been hid. Les ties this to Genesis, where one of the names of deity shows God as everlasting and capable of hiding things, and says that is His prerogative. He did this: He kept it hid, Paul says, from the beginning of the world, and it was hid in God, the same God who created all things by Jesus the Christ.