Goliath
Goliath is described in the biblical Book of Samuel as a Philistine giant defeated by the young David in single combat. The story signified Saul's unfitness to rule, as Saul himself should have fought for the Kingdom of Israel.
David in Islam
David's narrative in the Qur’an, in many respects, parallels that given in the Bible. Although he is never explicitly named a prophet ("nabī") or a messenger ("rasūl"), David is included in lists of those who received revelation ("waḥy"; 4:163) or guidance ("hudā"; 6:84) from God. In both lists his name appears next to that of his son Solomon. Elsewhere, the Quran explains that God gave to both of them the gifts of "sound judgment" ("ḥukm"; 21:79) and "knowledge" ("ʿilm"; 21:79; 27:15). Yet the Quran also ascribes to David merits that distinguish him from Solomon: David killed Goliath (2:251) and received a divine revelation named the Psalms (17:55 uses an indefinite form while 21:105 uses the definite form "al-zabūr"), presumably a reference to the Psalms or the Psalter (the term "zabūr" is perhaps related to Hebrew "mizmōr" or Syriac "mazmūrā", "psalm"). The mountains and the birds praised God along with David (21:79; in 34:10 God commands them to do so; cf. Psalm 148:7–10). God made David a "vicegerent" ("khalīfa"; 38:26), a title that the Quran otherwise gives only to Adam (2:30). This title suggests that, to the Quran, David was something more than a messenger: he was a divinely guided leader who established God’s rule on earth. This role is also suggested by 2:251: "God gave him authority ("mulk") and wisdom ("ḥikma") and taught him what He willed. If God did not drive back some people by others, the earth would become corrupt."