For our commonwealth has its existence in the heavens, from which also we await the Lord Jesus Christ as Saviour
— Philippians 3:20 Darby
Christ is the constitution of our heavenly commonwealth. In the heavens, Christ is the unique center. He is the totality of all that God is and the reality of heaven. Therefore, in this commonwealth we have nothing but Christ Himself. Heaven is heavenly only because Christ is there. He is the essence, the element, and the substance of our heavenly commonwealth.
Excerpted from Philippians: That I May Gain Christ by Titus Chu, pp. 244-245