Faith in Jesus Christ
Regardless of whether one is a physical Jew or a Gentile, only those who believe in Jesus Christ can become the spiritual descendant of Abraham (Gal 3:14). Thus we must have "faith" in Jesus Christ. Also, Gal 3:7 states, "Therefore, be sure that it is those who are of faith who are sons of Abraham." Also, Galatians 3: 29 states, "And if you belong to Christ, then you are Abraham's descendants, heirs according to promise."
The Matthean genealogy
When we look at the Matthean genealogy, it powerfully proclaims to all nations of the world that Jesus Christ is the Messiah who came as the son of Abraham (Matt 1: 1). And who is Jesus Christ? He is the promised seed (Gal 3: 19), and we become Abraham's spiritual descendants by believing in Jesus Christ. Therefore, we all become descendants of Abraham by belonging to Jesus Christ, and will be blessed with Abraham (Gal 3: 9).
The blessings of the spiritual descendants of Abraham
We, who have become descendants of Abraham through faith in Jesus Christ, receive the following blessings with Abraham. First, we are freed from all curses. Galatians 3:13 states the following: "Christ redeemed us from the curse of the Law, having become a curse for us— for it is written, 'Cursed is everyone who hangs on a tree.'" Secondly, we receive God's righteousness as a gift when we believe in Jesus Christ. Romans 3: 22 states, "...even the righteousness of God through faith in Jesus Christ for all those who believe; for there is no distinction." Galatians 3: 24 also states, "...so that we may be justified by faith." This is the doctrine of justification by faith. And it teaches us that salvation does not come through man's good works; salvation comes by faith and through God's grace.Thirdly, we become children of God. Thus, those who believe in Jesus Christ not only become righteous, but they also become sons of God (Gal 3: 26) by adoption. In the Bible, an adopted son is one who has become a child of God through redemption by the precious blood of Jesus Christ. It is the process where the people— who were by nature children of wrath, children of darkness, and children of Satan (Eph 2: 3; John 8: 44) — become children of blessings, children of the light, and children of God ((Isa 65: 23; John 1: 12). Fourthly and lastly, the spiritual descendants of Abraham are enabled to live by faith. Galatians 3: 11 states, "Now it is evident that no one is justified before God by the law, for 'The righteous shall live by faith'" (ESV). What kind of person lives by faith? A person who lives by faith is one who has been crucified on the cross with Jesus Christ (Gal 2: 20). People who belong to Jesus Christ have crucified the flesh with its passions and desires (Gal 5: 24).
Why must we die on the cross with Jesus?
First, when our old self is crucified on the cross, our body of sin is destroyed, and we no longer live as slaves to sin (Rom 6: 6). We do not let our bodies obey its lusts (Rom 6: 12). Nor do we lend the members of our body to sin as instruments of unrighteousness; rather, we present ourselves to God as instruments of righteousness (Rom 6: 13). To whomever we may present ourselves as slaves for obedience, we become slaves of the one whom we obey— either of sin resulting in death or of obedience resulting in righteousness (Rom 6: 16-19).
Conclusion: By dying on the cross with Jesus, we shall also live with Him (Rom 6: 8). Romans 6: 5 states, "For if we have become united with Him in the likeness of His death, certainly we shall also be in the likeness of His resurrection." Therefore, those who have been crucified and raised with Jesus walk in newness of life (Rom 6: 4). They live every day with God in the newness of life. I pray that we will savor eternal life every day with Christ as we walk with Him all the way now and forever. Rom 6:4 says, "Therefore we have been buried with Him through baptism into death, so that as Christ was raised from the dead through the glory of the Father, so we too might walk in newness of life."