The believer's union in Christ is the all-embracive reality of his redemption. This doctrine is the single, unifying theme of our relationship with God in and through Christ. Scripture bears copious testimony in this respect. For example, believers are elected unto salvation by God the Father in eternity past in Christ, Eph 1:3,4. In time we are united with Him in His death and resurrection, Rom 6:2-11.
Divine Self-revelation to human creatures is always downward. God's revelation of Himself to His creatures is always a condescending act. He stoops down; He lowers Himself to our level so that we might know Him. Without this sovereign initiative, we would never know anything about Him.