9 Also to enlighten all men and make plain to them what is the plan [regarding the Gentiles and providing for the salvation of all men] of the mystery kept hidden through the ages and concealed until now in [the mind of] God Who created all things by Christ Jesus.10 [The purpose is] that through the church the complicated, many-sided wisdom of God in all its infinite variety and innumerable aspects might now be made known to the angelic rulers and authorities (principalities and powers) in the heavenly sphere.11 This is in accordance with the terms of the eternal and timeless purpose which He has realized and carried into effect in [the person of] Christ Jesus our Lord,12 In Whom, because of our faith in Him, we dare to have the boldness (courage and confidence) of free access (an unreserved approach to God with freedom and without fear).
V9 Paul admits that there is a mystery involved with the life in Christ. That it was kept hidden in the past, and is now brought to light through his ministry.
The access to God has been made available through faith in Christ. Christ gives us the courage and confidence to have access, access which is an unreserved approach to Him without fear. There should not be any fear when accessing God. He wanted us to have access to Him, and therefore sent His Son to become the gate wherein we could open upon acceptance.