1 Corinthians 8:9 warns against making your freedom a stumbling block; 8:12 then declares that doing so is sin against Christ.

In 1 Corinthians 12:12, believers are one body in Christ — so harming a member harms Christ, directly explaining Paul's logic.

In Exodus 16:8, grumbling against Moses is grumbling against God — directly parallels sinning against a brother as sin against Christ.

In Matthew 18:10, Jesus warns against despising 'little ones' whose angels see God—the same vulnerable believers Paul says sinning against wounds Christ.

Matthew 25:40 directly identifies service to 'the least of these my brothers' as service to Christ—matching Paul's sin-against-brother equals sin-against-Christ.

Matthew 25:45 shows neglecting the least is neglecting Christ—the negative mirror of Paul's point that harming weak brothers harms Christ.

In Acts 9:4, Jesus asks Saul 'why are you persecuting me?'—directly identifying with His people, just as Paul identifies Christ with weak brothers.

Acts 9:5 confirms Jesus personally identifies: 'I am Jesus, whom you are persecuting'—the same identity Paul applies to sinning against brothers.

Luke 17:2 says causing a 'little one' to sin is worth death by millstone—the same serious offense Paul describes as sinning against Christ.

Romans 14:15 echoes the same principle: causing a brother to stumble by food is sinning against love and Christ.

In Matthew 12:49, Jesus calls disciples his brothers — so sinning against them is sinning against Christ, as Paul states.