This Bible contradiction is from the Skeptic's Annotated Bible.
1 Samuel 21:1 View context
Then came David to Nob to Ahimelech the priest: and Ahimelech was afraid at the meeting of David, and said unto him, Why [art] thou alone, and no man with thee?
Mark 2:25-26 View context
And he said unto them, Have ye never read what David did, when he had need, and was an hungred, he, and they that were with him?
How he went into the house of God in the days of Abiathar the high priest, and did eat the shewbread, which is not lawful to eat but for the priests, and gave also to them which were with him?