What does it mean to be the seed of Abraham?

TL;DR:

The seed of Abraham includes both physical descendants and spiritual followers, but true relationship with God comes through faith in Him. Salvation and God’s promises are inherited not by ancestry, but by living in faith like Abraham.

what does the bible say?

Scripture describes God calling Abraham from his home country to the land of Canaan and promising to make a great nation of him (Genesis 12). Abraham had two sons, Ismael (Genesis 16) and Isaac (Genesis 21). Isaac was the son of God’s promise to Abraham, the son from which the nation of Israel would come (Genesis 15:4-5). In the New Testament, the religious leaders put their confidence in their lineage, thinking it would save them, but both John the Baptist and Jesus confronted them with their error (Matthew 3:7-9; John 8:33-44): Being physically from Abraham’s lineage is not what saves them. Being the spiritual sons and daughters of Abraham—i.e., those who have faith in Christ—is the only way to salvation (Galatians 3:28-29).

from the old testament

Abraham was counted as righteous because he had faith in God (Genesis 15:6). Spiritually, those who believe, put their faith in God's Son, exhibit an Abrahamic faith by which they are counted as righteous.

from the new testament

Both John the Baptist and Jesus confronted Jewish leaders who counted on their lineage from Abraham to save them, but failed to grasp the faith relationship Abraham had with God. John called on them to repent: "Bear fruit in keeping with repentance. And do not presume to say to yourselves, 'We have Abraham as our father,' for I tell you, God is able from these stones to raise up children for Abraham" (Matthew 3:8–9).
In John 8:33-59, Jews sought to kill Jesus, repeatedly establishing their connection with Abraham and therefore with God. Jesus confronts them, telling them that the true descendants of Abraham would do as He did (live by faith in God rather than by rules). Jesus reveals that He knew Abraham, then asserts His divinity by indicating that He existed before Abraham was born (John 8:58).
Only a right relationship with God can define a spiritual descendant of Abraham. As Paul says, "For no one is a Jew who is merely one outwardly, nor is circumcision outward and physical. But a Jew is one inwardly, and circumcision is a matter of the heart, by the Spirit, not by the letter. His praise is not from man but from God" (Romans 2:28–29).
More directly, Galatians 3:28-29 says, "There is neither Jew nor Greek, there is neither slave nor free, there is no male and female, for you are all one in Christ Jesus. And if you are Christ's, then you are Abraham's offspring, heirs according to promise."

implications for today

Ancestry tests can be fun. You may find out you’re a distant, distant cousin of George Washington or that you share DNA markers with King Richard. It’s all exciting —- until you realize that millions of others can claim the same.

All true Christians today can claim spiritual ancestry with Abraham, a man God called a “friend” (James 2:23). And as Christians, we join a family of believers that can often be closer than our blood relatives. In fact, Jesus said “whoever does the will of my Father in heaven is my brother and sister and mother” (Matthew 12:50).

This means that we should treat our spiritual family with the kindness and love of a true family. That may mean visiting someone who is sick, inviting a fellow Christian for a meal, or mowing a widow’s lawn. In the end, our physical ancestry may produce some interesting connections but nothing that is more important than the link that all believers share: Our faith in and love for Christ and all He stands for.

understand

True descendants of Abraham are defined by faith, not ancestry.
Abraham’s righteousness came through faith, which believers share spiritually.
Christians are Abraham’s spiritual family.

reflect

How does knowing that you are a spiritual descendant of Abraham through faith shape how you understand your identity within the family of God?
How are you actively living out the faith that connects you to Abraham’s legacy?
How can you show love and support to your spiritual family as part of Abraham’s offspring?

engage

How does the truth that faith saves us and brings us into the family of God, not physical lineage, challenge or strengthen our understanding of God’s promises?
How can we encourage one another to live by faith like Abraham in today’s world?
How does being part of Abraham’s spiritual family impact how we interact with Christians from different backgrounds or cultures?