Romans 9:16 explains that mercy depends on God, not human will—immediate context reinforcing the same point in 9:18.

Romans 9:15 provides the OT quote (Exodus 33:19) that grounds Paul's statement on mercy and hardening in 9:18.

Romans 9:21 uses the potter/clay analogy to reinforce God's sovereign authority over mercy and hardening.

In Romans 11:8, Paul cites Scripture to show God gave Israel a spirit of stupor, exemplifying the hardening he describes in 9:18.

Romans 11:7 directly states 'the rest were hardened'—continuation of the hardening theme from Romans 9:18.

Romans 1:24-28 shows God 'giving them up' to sin—parallel to God hardening in 9:18; both depict divine judicial action.

In Exodus 7:13, Pharaoh's heart is hardened as God said, demonstrating the hardening that Romans 9:18 attributes to God's will.

In Exodus 4:21, God declares He will harden Pharaoh's heart, the very example Paul uses in Romans 9:17-18 to illustrate divine hardening.

In Matthew 11:25, Jesus thanks God for hiding truth from some and revealing to others — a clear parallel to God's sovereign mercy and hardening.

John 12:40 quotes Isaiah about God hardening hearts, directly illustrating God's sovereign hardening as in Romans 9:18.

Hosea 2:4 announces God will not have mercy on Israel's children, directly illustrating the withholding of mercy described in Romans 9:18.

Isaiah 43:13 asserts God's irreversible actions — underpinning the unchallengeable divine will behind both mercy and hardening in Romans 9:18.

Job 9:12 declares that no one can question God's actions — reinforcing the sovereign prerogative of mercy and hardening in Romans 9:18.

Exodus 10:20 directly states the Lord hardened Pharaoh's heart, a clear instance of the hardening referenced in Romans 9:18.

Exodus 9:7 shows Pharaoh's heart hardened after God's plague, exemplifying the hardening Romans 9:18 attributes to God's will.

In Acts 28:26-28, Paul quotes Isaiah about Israel's hardening and turns to Gentiles, reflecting Romans 9:18's theme of hardening and mercy.

In Joshua 11:20, the LORD hardens the Canaanites' hearts to destroy them, illustrating the same sovereign hardening as Romans 9:18.

In Deuteronomy 2:30, God hardens Sihon's heart to deliver him to Israel, another OT example of divine hardening like in Romans 9:18.

In Isaiah 63:17, the prophet asks why God hardens Israel's heart, echoing the divine hardening principle of Romans 9:18.

In Matthew 13:15, the people's hearts are dull and eyes closed, illustrating the hardening that Romans 9:18 speaks of.

1 Corinthians 12:11 affirms the Spirit distributes gifts as He wills, echoing the same sovereign will in Romans 9:18.

In 2 Thessalonians 2:10-12, God sends a strong delusion to those who reject truth, similar to the hardening in Romans 9:18.

Deuteronomy 7:7 explains God's choice of Israel was based on his love, not merit — echoing God's sovereign mercy in Romans 9:18.