One of the classic themes in replacement theology (the belief that Christians have “replaced” the Jews in covenant relationship with God) is that even stones can be turned into God’s children. A number of new testament texts (i.e. Luke 3:7-8) are commonly used to support this traditional theology.
For example, John the Baptist spoke to his fellow Judeans:
“You brood of vipers, who warned you to flee from the wrath to come? Therefore, bear fruits in keeping with repentance, and do not begin to say to yourselves, ‘We have Abraham for our father,’ for I say to you that from these stones God is able to raise up children to Abraham.” (Luke 3:7-8)
The mistaken assumption is that these texts are describing a “Jews” versus “Gentiles” mentality, while in reality they are contrasting “Jews” and “Better Jews” instead. This Jewish prophet confronted his fellow Jews who thought that they can go through his water-washing without true life-changing repentance and still receive God’s pardon. In a similar incident, Jesus, in his confrontation with some Judeans who opposed him said, “If you are Abraham’s children, do the deeds of Abraham.” (John 8:39)
Finally, those who embrace replacement theology often cite Paul’s words to the Christ-following assembly in Rome to (wrongly) support their view that Christians have replaced the Jews as God’s uniquely chosen people:
“…not as though the word of God has failed. For they are not all Israel who are from Israel; nor are they all children because they are Abraham’s descendants, but: ‘through Isaac your descendants will be named.’ That is, it is not the children of the flesh who are children of God, but the children of the promise are regarded as descendants.” (Rom. 9:6-8)
An ancient Jewish prayer (Ribon Kol HaOlamim) used regularly today sheds light on the error that Jesus, John the Baptist, and Paul were all attempting to correct.
“Master of Eternity, it is not because of our righteousness that we bring before you our supplications, but because of your great mercy. What is our faithfulness?! What is our righteousness?! …What can be possibly said before you, Lord God, God of our Fathers?! …but we are children of your beloved Abraham, to whom You swore on Mount Moriah. We are the seed of Isaac his only son, who was bound on the altar. We are the witnessing community of Jacob, chosen and loved to the utmost by You…”
The child of the flesh is Ishmael, while the child of the promise is Isaac (notice that both Isaac and Ishmael were living, breathing sons of Abraham!). The contrast between Isaac and Ishmael is not between two different “races” but between two sons of the same father, who chose to relate to God in radically different ways: one in faithfulness (Gen.22) and the other in rebellion (Gen. 16:12). Isaac’s life throughout the Book of Genesis was characterized by faith and obedience to God. Isaac was not only related to his father by blood, but also by living (and receiving God’s favor) the same way that his dad did – by grace through faith.
In other words, John the Baptist, Paul, and Jesus all agree that while the connection with Abraham is very special, it is an “Abraham-like” faithful and trusting living under the blessed promise of God that reconfirms a person’s ultimate “belonging” to Israel.