Paul's letter to the Romans is recognized as foundational theology. Ephesians has a similar status undoubtedly due to "the surpassing greatness of the revelations" (2Co 12:7). They are matched by the "surpassing greatness of His power toward us who believe" (Eph 1:19). The revelations according to the Greek word huperbole are superior or beyond measure which means that to some people might sound excessively religious or impractical. But to those who "having also believed" (:13) and have "faith in the Lord Jesus" (:15) the doctrine is valuable to "know what is the hope of His calling" (:18). "We have obtained an inheritance having been predestined . . . to the end that we . . . would be to the praise of His glory" (:11-12). It is "Christ in you, the hope of glory" (Col 1:27). Then the Holy Spirit "is given as a pledge (NASB), deposit guaranteeing (NIV), earnest (KJV), guarantee (RSV) of our inheritance" (:14). "In Him we have redemption through His blood" (:7). "You were bought with a price; do not become slaves of men" (1Co 7:23). We "were sealed in Him with the Holy Spirit of promise" (Eph 1:13) "with a view to the redemption . . . to the praise of His glory" (:14). "For the Lord will not abandon His people, nor will He forsake His inheritance" (Ps 94:14). An inheritance happens after "the death of the one who made" (Heb 9:16) the covenant. We are to know "what are the riches of the glory of His inheritance in the saints" (Eph 1:18) who are "God's own possession" (:14). You are redeemed at salvation so "the redemption of the purchased possession" (:14) occurs in the future kingdom. We are "awaiting for our adoption as sons, the redemption of our body" (Ro 8:23). "The anxious longing of the creation waits eagerly for the revealing of the sons of God" (:19).
"When the fullness of time came, God sent forth His Son . . . so that He might redeem those who were under the Law, that we might receive the adoption as sons" (Gal 4:4-5). Redemption pertains to purchasing slaves or prisoners to set them free as when we "were held in bondage under the elemental things of the world" (:3). In the ancient world adoption was a legal process where a person was brought into a family and placed as a son with the same privileges as a biological child. "Therefore you are no longer a slave, but a son; and if a son, then an heir through God" (:7). An heir is "owner of everything" (:1). "You have received a spirit of adoption as sons" (Ro 8:15) and "because you are sons, God has sent forth the Spirit of His Son into our hearts, crying, 'Abba Father!'" (Gal 4:6) whereby we know "we are children of God" (Ro 8:16). We are also "fellow heirs with Christ, if indeed we suffer with Him so that we may also be glorified with Him" (:17). "The sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us" (:18). "The creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God" (:21).