Contradiction with Hebrews 6:4-6
These verses suggest that it is possible to fall away after receiving enlightenment, which contradicts the assurance in 1 Corinthians 1:8 that believers will be confirmed blameless.
Hebrews 6:4-6: For [it is] impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost,
Contradiction with 2 Peter 2:20-22
This passage implies the possibility of believers returning to a sinful state, opposing the promise of being kept blameless in 1 Corinthians 1:8.
2 Peter 2:20-22: For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning.
Contradiction with Revelation 3:5
The condition of having one's name not blotted out of the book of life contrasts with the certainty presented in 1 Corinthians 1:8.
Revelation 3:5: He that overcometh, the same shall be clothed in white raiment; and I will not blot out his name out of the book of life, but I will confess his name before my Father, and before his angels.
Contradiction with Matthew 24:13
The need for endurance to be saved can be seen as contradictory to the assurance of being blameless until the end in 1 Corinthians 1:8.
Matthew 24:13: But he that shall endure unto the end, the same shall be saved.
Contradiction with Galatians 5:4
Falling from grace is mentioned here, which contrasts with the idea of being confirmed blameless in 1 Corinthians 1:8.
Galatians 5:4: Christ is become of no effect unto you, whosoever of you are justified by the law; ye are fallen from grace.