Contradiction with 2 Samuel 21:19
This verse records a different account of who killed Goliath, which potentially contradicts the roles and recognitions of warriors in David's time.
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 Samuel 17:50
It describes David as the one who killed Goliath, contradicting any reference to other warriors being credited with similar feats.
1 Samuel 17:50: So David prevailed over the Philistine with a sling and with a stone, and smote the Philistine, and slew him; but [there was] no sword in the hand of David.