When He ascended, He was resurrected as very God. He was an immortal spirit Being once again!
These verses show the goal, the focus, the very reason the church exists—why we have been given the Spirit of God: "till we come to the unity of the faith and the knowledge of the Son of God." Paul is describing something that will not occur while we are still physical beings, pointing to the great goal that lies beyond the resurrection of the dead!
We find our hope and goal in verse 13. We must begin to expand on what Jesus Christ is now—that is what the apostle Paul points to. Our standard is not Jesus merely as a man before He was crucified and resurrected, but the great goal is becoming like Jesus Christ is now—ascended and at God's right hand!
We are still mortal and physical, but we are in the image of God (Genesis 1:26), not just in form and shape. The image of God that He is concerned about is the fact that we have the power of mind. Because of this, and with the help of the gifts of God, particularly His Spirit, we can come to the measure of the stature of the fullness of Christ.
John W. Ritenbaugh