Romans 9:4 lists ethnic Israel's privileges — setting up the tension that not all of them belong to true Israel, as v6 clarifies.

In Romans 2:29, Paul defines a Jew by inward circumcision of the heart, reinforcing that true Israel is spiritual, not ethnic.

Romans 3:3 asks whether Jewish unfaithfulness nullifies God's faithfulness — the same question Paul answers in Romans 9:6, that God's word hasn't failed.

In Romans 4:12-16, Paul argues Abraham's children are those who share his faith, not just his bloodline — exactly the logic here.

In Romans 11:1, Paul himself is an Israelite, showing God hasn't rejected His people — direct evidence that the word hasn't failed.

Romans 11:2 adds that God foreknew His people and cites Elijah, proving a faithful remnant exists despite apparent failure.

Romans 4:11 shows Abraham is father of all believers, not just ethnic Jews — this grounds Paul's distinction in Romans 9:6.

Hebrews 6:18 states it's impossible for God to lie — further confirming that His word to Israel cannot fail.

Hebrews 6:17 shows God guaranteed His promise with an oath, emphasizing the unchangeable purpose behind His word to Israel.

In Galatians 6:16, Paul prays peace on the 'Israel of God,' likely referring to believers as the true Israel, echoing this distinction.

Revelation 2:9 mentions those who 'say they are Jews and are not' — directly parallels Paul's distinction between ethnic and true Israel.

In Genesis 17:19, God chooses Isaac over Ishmael for the covenant, illustrating that not all Abraham's descendants are God's chosen people.

1 John 2:19 says those who left were never truly of us — parallels Paul's principle that not all ethnic Israelites are true Israel.

Isaiah 48:1 describes those called Israel but not in truth — directly parallel to Paul's point that not all descended from Israel belong to Israel.

In Genesis 17:21, God reiterates that his covenant is with Isaac, not Ishmael — a direct example of selective promise.

In John 1:47, Jesus calls Nathanael a true Israelite without deceit, showing that genuine Israel is marked by character, not ancestry.

In Psalm 73:1, God is good to Israel, to the pure in heart — linking true Israel with purity, which parallels the inward definition here.