What is our glorious calling and glory? To be like God (Eph. 1.4) and to glorify God.
What is our inheritance? We are God's inheritance (Eph. 1.18), but what is our inheritance? We don't have an inheritance. The Bible explicitly says we are God's inheritance. "We were made a heritage" (Eph. 1.11). "Foreordained" (Eph. 1.5,11) to be sons, we who believe. Foreordained because we chose God, and God foreknew our choice, not pre-making our choice. It was something left up to us so that no pride exists and no superficial purpose of God exists. So God inherits us believers. The Son of God will bring many sons into glory (Gal. 4.6; Heb. 2.10).
What is the eternal purpose and plan of God? There is no rest, no day of satisfaction until God's work is in vision with with His plan completely so that what our hearts are burdened with and our hands engaged in are nothing but what God desires to have. Let us stay in this vision, and ask God to keep us in this vision. Never forget in reaching that day of many sons in glory.