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

Verses

Both thieves reviled Jesus.

Mark 15:32 View context

Let Christ the King of Israel descend now from the cross, that we may see and believe. And they that were crucified with him reviled him.

Matthew 27:44 View context

The thieves also, which were crucified with him, cast the same in his teeth.

Only one thief reviled Jesus.

Luke 23:39-42 View context

And one of the malefactors which were hanged railed on him, saying, If thou be Christ, save thyself and us.

But the other answering rebuked him, saying, Dost not thou fear God, seeing thou art in the same condemnation?

And we indeed justly; for we receive the due reward of our deeds: but this man hath done nothing amiss.

And he said unto Jesus, Lord, remember me when thou comest into thy kingdom.