Paul’s question, “what advantage has the Jew?” comes immediately on the heels of his distinction between those who are Jews inwardly and those who are Jews outwardly. He knew that the moment he made that distinction that he faced the same sort of problem he would address in Romans 9: if it is all down to election, then what value is the visible church? His answer: “much in every way.” He says so because it is through the visible assembly that God the Spirit operates to call his elect to new life and to true faith in the Jesus the Messiah.
A correspondent to the HB writes to ask, “According to Paul, who are Abraham’s children?” In one way or another, I get this question frequently. Most American evangelicals have been taught some version of Dispensational theology or are otherwise influenced by it so that they use a similar way of reading Scripture without realizing how they have been influenced by Dispensationalism. As a consequence, most American evangelicals seem unaware of the ways the Abrahamic covenant unifies redemptive history. Here’s one attempt to sketch this significance of the Abrahamic covenant for understanding the redemptive history. Heidelberg Catechism 74 speaks to this directly. Reformed Christians initiate their children into the visible covenant community (the visible church) on the basis of the divine command and promises given to Abraham, who has a distinct and more fundamental role in the history of redemption than Moses did. Abraham was not Moses and may not be treated as if he were just an earlier version of Moses. As Hebrews 3:1–6 says, the latter was a servant in God’s house, but Jesus is the Son and the heir. Believers are described as “offspring of Abraham” (Heb 2:16). Paul contrasts the Mosaic and Abrahamic covenants in Galatians chapters 3 and 4. In Galatians 3:15–18 Paul observes that the Abrahamic covenant is permanent but the Mosaic covenant, which Jeremiah 31:31–34 contrasted with the “new covenant,” which Paul called the “old” and “fading” covenant in 2 Corinthians 3, and which Hebrews calls the inferior and “obsolete” covenant (7:22; 8:13), was intentionally temporary. There are two cities, the earthly city and the heavenly (Gal 4). The new covenant is the new administration of the Abrahamic covenant.
Second, before we answer the question directly, it is also important to understand that there are three ways of relating to the covenant of grace: outside, internally, and externally. These are categories that Scripture itself gives us for addressing this question.
So, in light of all this, who are Abraham’s children? Those who are most truly Abraham’s children are the elect, who, in time, have been or shall be brought to new life and true faith whereby they receive the promised benefits of the Abrahamic covenant. This is the teaching of our Lord in John 8:
They answered him, “Abraham is our father.” Jesus said to them, “If you were Abraham’s children, you would be doing the works Abraham did, but now you seek to kill me, a man who has told you the truth that I heard from God. This is not what Abraham did (John 8:39–40; ESV).
According to Paul, believers are “Jews inwardly” (Rom 2:28–29; 9:6) but outwardly, all those who participate in the external administration of the covenant of grace are reckoned as Abraham’s children. Romans 2:28–29 say:
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 (ESV).
In Romans 9:6–8 Paul added:
But it is not as though the word of God has failed. For not all who are descended from Israel belong to Israel, and not all are children of Abraham because they are his offspring, but “Through Isaac shall your offspring be named.” This means that it is not the children of the flesh who are the children of God, but the children of the promise are counted as offspring (ESV).
From this some have inferred that all that matters is election and that the outward or external, visible administration of the covenant of grace is unimportant but Paul begs to differ.