Contradiction with 2 Samuel 21:19
This verse states that Elhanan killed Goliath, contradicting the account in 1 Samuel 17, where David is credited with Goliath's death.
2 Samuel 21:19: And there was again a battle in Gob with the Philistines, where Elhanan the son of Jaareoregim, a Bethlehemite, slew [the brother of] Goliath the Gittite, the staff of whose spear [was] like a weaver's beam. [Jaareoregim: or, Jair]
Contradiction with 1 Chronicles 20:5
Similar to 2 Samuel 21:19, this verse attributes the killing of Goliath to Elhanan, again contradicting 1 Samuel 17's attribution to David.
1 Chronicles 20:5: And there was war again with the Philistines; and Elhanan the son of Jair slew Lahmi the brother of Goliath the Gittite, whose spear staff [was] like a weaver's beam. [Jair: also called, Jaareoregim]