CLAIM: Jesus claimed that Abiathar was the high priest at the time of Christ. However, 1 Samuel 21:1-6 states that the high priest was actually Ahimelech. Critic Bart Ehrman explained that this “mistake” in the Bible led him to begin doubting the authority and inerrancy of Scripture.
RESPONSE: Jesus didn’t specifically affirm that Abiathar was the high priest. Instead, Jesus said, “He entered the house of God in the time of Abiathar the high priest” (Mk. 2:26). In the very next chapter of 1 Samuel, Saul had Ahimelech killed, so Abiathar took over as high priest (1 Sam. 22). Therefore, he was alive and involved turning this period that Jesus mentioned. Jesus identified him as the high priest to identify him as a historical figure. This would be similar to referring to referring to President Bill Clinton meeting President John F. Kennedy as a teenager. While Clinton wasn’t the President yet, it would still be perfectly appropriate to refer to him as the President to easily identify him.
John Wenham may have the best solution (as usual!). He noted that Mark used the same construction (epi Abaithar archiereōs) to refer to Moses “in the account of the bush” (epi tou batou, Mk. 12:26). Thus, this could be rendered “in the account of Abiathar the high priest.” Lane concurs, “Mark may have inserted the reference to Abiathar to indicate the section of the Samuel scroll in which the incident could be located.” This makes a considerable amount of sense—especially “since Abiathar was the only survivor of the slaughter of the priests of Nob (22:20) and in fact became much more noteworthy than his father.”
 Bart D. Ehrman, Misquoting Jesus: The Story behind Who Changed the Bible and Why (New York: Harper, 2005), p.9.
 That is, both use the genitive to describe this era of history. J. W. Wenham, “Mark 2, 26,” JThS n.s. 1 (1950), p. 156.
 Lane, W. L. (1974). The Gospel of Mark (p. 116). Grand Rapids, MI: Wm. B. Eerdmans Publishing Co.
 Youngblood, R. F. (1992). 1, 2 Samuel. In F. E. Gaebelein (Ed.), The Expositor’s Bible Commentary: Deuteronomy, Joshua, Judges, Ruth, 1 & 2 Samuel (Vol. 3, p. 728). Grand Rapids, MI: Zondervan Publishing House.