Luke 11:26
Then goeth he, and taketh to him 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.
Cross-reference
Matthew 12:45
Parallel
Matthew 12:45 records Jesus' identical teaching about the returning unclean spirit — a direct synoptic parallel reinforcing the warning.
Hebrews 6:4–8
Parallel
Hebrews 6:4-8 describes those who experienced spiritual renewal then fall away, becoming impossible to restore — akin to the final worse state.
Hebrews 10:26–31
Related theme
Hebrews 10:26-31 warns that willful sin after receiving truth brings fearful judgment — a parallel to the worse outcome after cleansing.
2 Peter 2:20–22
Parallel
2 Peter 2:20-22 directly echoes that those who escape defilement then return to it are worse off — almost a commentary on Luke 11:26.
John 5:14
Related theme
John 5:14 warns the healed man to sin no more lest a worse thing happen — mirroring the danger of relapse into a worse condition.