John 10:4 explains sheep follow because they know the shepherd's voice — underlies why not being a sheep leads to unbelief here.

John 10:27 describes sheep hearing and following — directly contrasts with those who don't believe because not sheep.

John 6:37 says all given by Father come to Jesus — same divine election logic: not being a sheep means not given.

John 6:44 says no one can come unless drawn by Father — parallels the inability to believe without being a sheep.

John 6:45 says those taught by God come to Jesus — not being a sheep means not having heard from the Father.

In John 6:65, Jesus teaches that coming to him is granted by the Father — same reason why some do not believe: divine enablement.

John 8:47 states that those who are of God hear God's words; not being of God explains why they don't believe — identical logic.

John 12:37-40 quotes Isaiah that God blinded their eyes — explains the cause behind not being sheep: divine hardening.

John 3:19 explains that people love darkness instead of light — the same root cause of unbelief that Jesus attributes to those who are not his sheep.

John 6:64 records Jesus' knowledge that some do not believe — directly paralleling his statement here that unbelief stems from not being his sheep.

In John 18:37, Jesus says everyone of the truth listens to his voice, paralleling the idea that his sheep hear him — explaining why unbelievers are not his sheep.

1 John 4:6 says whoever is not from God does not listen — directly echoes 'you do not believe because you are not my sheep'.

2 Corinthians 4:4 adds that Satan blinds unbelievers — a specific mechanism behind the unbelief of non-sheep.

2 Corinthians 4:3 says the gospel is veiled to those perishing — parallel to not believing because not sheep.

Romans 11:8 cites God giving a spirit of stupor — same hardening theme as John 10:26's unbelief.

Romans 11:7 explains that Israel failed to obtain righteousness because the rest were hardened — parallels the elect vs. non-sheep.

In Acts 13:48, belief is linked to being appointed to eternal life, paralleling Jesus' statement that unbelief stems from not being his sheep.

Luke 22:67 shows Jesus telling the Sanhedrin they will not believe even if he tells them — a direct parallel to the unbelief of those who are not his sheep.

In 1 Corinthians 2:14, the natural person cannot accept spiritual truths, just as Jesus says unbelievers cannot believe because they are not his sheep.

Matthew 25:33 depicts the final separation of sheep and goats, reinforcing the sheep metaphor for believers that Jesus applies to his followers here.

In Ezekiel 34:31, God calls Israel his sheep, establishing the covenant metaphor Jesus uses to identify his true followers here.

Luke 12:32 calls disciples a 'little flock' — the same shepherd-flock imagery Jesus uses to distinguish his sheep from unbelievers.

Psalm 100:3 defines God's people as sheep of his pasture — provides OT background for Jesus' 'my sheep' metaphor.