This Bible contradiction is from the Skeptic's Annotated Bible.

Verses

God revealed it to him; no human told him.

Matthew 16:16-17 View context

And Simon Peter answered and said, Thou art the Christ, the Son of the living God.

And Jesus answered and said unto him, Blessed art thou, Simon Bar-jona: for flesh and blood hath not revealed [it] unto thee, but my Father which is in heaven.

His brother Andrew told him.

John 1:40-41 View context

One of the two which heard John [speak], and followed him, was Andrew, Simon Peter's brother.

He first findeth his own brother Simon, and saith unto him, We have found the Messias, which is, being interpreted, the Christ.