Contradiction with 1 Thessalonians 5:2-3
While Luke 21:35 states the day will come as a snare, unseen, sudden destruction in 1 Thessalonians 5:3 contradicts the warning aspect since people will claim "peace and safety" before it occurs.
1 Thessalonians 5:2-3: For yourselves know perfectly that the day of the Lord so cometh as a thief in the night.
Contradiction with Matthew 24:36
Luke 21:35 implies a targeted event on "all them that dwell on the face of the whole earth," suggesting a specific certainty, whereas Matthew 24:36 emphasizes the unknown day and hour, reflecting uncertainty.
Matthew 24:36: But of that day and hour knoweth no [man], no, not the angels of heaven, but my Father only.
Contradiction with 2 Peter 3:10
Luke 21:35 describes an ensnaring event, but 2 Peter 3:10 depicts the day of the Lord as unexpected, like a thief, not characterized as a trap for all inhabitants.
2 Peter 3:10: But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.
Contradiction with Revelation 3:3
This verse implies alertness can prevent surprise, contrasting Luke 21:35's implication that the event will come upon everyone as a snare regardless of awareness or preparation.
Revelation 3:3: Remember therefore how thou hast received and heard, and hold fast, and repent. If therefore thou shalt not watch, I will come on thee as a thief, and thou shalt not know what hour I will come upon thee.