Abiathar in Wikipedia
Abiathar (אביתר, Ebyathar, Evyatar, the [divine] father is
pre-eminent), in the Hebrew Bible, son of Achimelech or
Ahijah, High Priest at Nob, the fourth in descent from Eli.
The only one of the priests to escape from Saul's massacre,
he fled to David at Keilah, taking with him the ephod (1
Sam. 22:20 f., 23:6, 9). He was of great service to David,
especially at the time of the rebellion of Absalom (2 Sam.
15:24, 29, 35, 20:25). In 1 Kings 4:4 Zadok and Abiathar are
found acting together as priests under Solomon. In 1 Kings
i. 7, 19, 25, however, Abiathar appears as a supporter of
Adonijah, and in 2:22 and 26 it is said that he was deposed
by Solomon and banished to Anathoth. In 2 Sam. 8:17
Abiathar, the son of Achimelech should be read, with the
Syriac, for Achimelech, the son of Abiathar. For a similar
confusion see Gospel of Mark 2:26. In reporting Jesus
words the evangelist has confused Abiathar with Ahimelech, a
mistake into which he was led by the constant association of
David‘s name with Abiathar. Suggestions made to evade the
difficulty - e.g. that father and son each bore the same
double name, or that Abiathar officiated during his father's
lifetime and in his father's stead - have been supported by
great names, but are baseless...