Romans 11:17 introduces the olive tree imagery of grafting; here the warning applies that imagery.

Romans 11:19 presents a prideful objection ('I was grafted in'); this verse corrects it with a warning.

Jeremiah 25:29 says judgment begins with God's own people, mirroring the logic that if God did not spare the natural branches, He won't spare you.

Jeremiah 49:12 warns that those who think they will escape judgment will be punished, similar to the warning here.

1 Corinthians 10:1-12 uses OT examples and ends with 'let him who thinks he stands take heed lest he fall', directly paralleling this warning.

2 Peter 2:4-9 cites examples of God's judgment to warn believers, reinforcing that God does not spare the unrighteous.

In Jude 1:5, God killed the Exodus generation after saving them — same warning that past deliverance doesn't guarantee future sparing.

Deuteronomy 29:20 describes God not forgiving covenant breakers — the same principle of no sparing for unfaithfulness.

Ezekiel 5:11 explicitly says 'My eye will not spare' — directly matching Paul's statement that God did not spare natural branches.

Hebrews 3:12 warns against an unbelieving heart that leads to falling away — the same danger Paul warns about for Gentiles.