Contradiction with Matthew 10:33
While John 13:38 predicts Peter's denial, Matthew 10:33 emphasizes the importance of not denying Christ.
Matthew 10:33: But whosoever shall deny me before men, him will I also deny before my Father which is in heaven.
Contradiction with 2 Timothy 2:12
John 13:38 foretells Peter's denial, whereas 2 Timothy 2:12 warns that denying Christ will result in being denied by Him.
2 Timothy 2:12: If we suffer, we shall also reign with [him]: if we deny [him], he also will deny us:
Contradiction with Romans 10:9
John 13:38 predicts Peter's denial of Jesus, whereas Romans 10:9 highlights the necessity of confessing faith in Jesus for salvation.
Romans 10:9: That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.
Contradiction with Matthew 26:41
John 13:38 speaks of Peter's denial, while Matthew 26:41 encourages staying vigilant and prayerful to avoid temptation.
Matthew 26:41: He went away again the second time, and prayed, saying, O my Father, if this cup may not pass away from me, except I drink it, thy will be done.
Contradiction with 1 John 4:15
John 13:38 mentions Peter's denial, whereas 1 John 4:15 states confessing Jesus as the Son of God brings mutual abiding with God.
1 John 4:15: Whosoever shall confess that Jesus is the Son of God, God dwelleth in him, and he in God.