Matthew 12:45
Then goeth he, and taketh with himself seven other spirits more wicked than himself, and they enter in and dwell there: and the last state of that man is worse than the first. Even so shall it be also unto this wicked generation.
Cross-reference
In Matthew 12:41, the Ninevites repented at Jonah's preaching — contrasting with this generation's rejection, which leads to the final worse state.
In Matthew 23:15, Jesus condemns making converts twice as much children of hell — mirroring the worsened final state of the cleansed man here.
In Matthew 23:32-39, Jesus declares that this generation will suffer the full measure of judgment — directly filling up the 'worse final state' of the unclean spirit.
Matthew 17:21 reveals that some demons require prayer and fasting to expel — the spiritual discipline needed to prevent the return described here.
Luke 11:26 is the parallel account of this same teaching about the returning unclean spirit, confirming the warning.
In 1 Thessalonians 2:15, the wrath that has come upon them to the uttermost matches the final state of the unclean spirit's return.
Hebrews 6:4-8 describes those who fall away after tasting grace, impossible to restore — thematically parallel to the final state worse than the first.
Hebrews 10:26-31 warns of worse punishment for deliberate sin after receiving truth, echoing the 'worse than the first' outcome here.
2 Peter 2:14-22 compares apostates to dogs returning to vomit — a direct parallel to the returning spirits making the end worse.
Proverbs 26:11 compares a fool returning to folly to a dog returning to its vomit — the same image of relapse into a worse condition.
Mark 9:29 teaches that some evil spirits require prayer and fasting to cast out — the same remedy against the returning spirit of Matthew 12:45.
Luke 11:25 is the parallel account of the unclean spirit, adding the detail of the house swept and put in order before the spirits return.
John 5:14 echoes the 'worse than the first' principle with Jesus' warning 'sin no more, that nothing worse happen'—a direct parallel to the worsening condition.
Mark 16:9 notes Mary Magdalene had seven demons cast out — echoes the seven more spirits brought back, using the same number for demonic activity.
In John 15:22-24, Jesus says their sin is greater because they saw His works and still hated — increased accountability parallels the 'worse' condition.
Mark 5:9 shows a legion of demons — parallels the multiple spirits in Matthew 12:45, both depicting numerous evil spirits.