In Bethlehem, David Brandon Engman is a young musician who tends his father Jesse's flock of sheep. After protecting the flock from an Asian lion, David is called before Prophet Samuel, who anoints him as the future King of Israel. Samuel leaves when palace guards arrive to retrieve David to play the lyre for King Saul Adam Michael Gold. David soothes Saul, who has become troubled as God has rejected him for his vices.
Saul is alerted when the Philistine army, led by King Achish Asim Chaudhry, do not arrive to battle the Israelite army. In the Valley of Elah, the Philistines bring forth their champion, Goliath Kamran Nikhad, a nine-foot giant. Goliath taunts Saul, his son Jonathan, and the Israelites to summon a worthy challenger. Firm in his faith in God, David decides to challenge Goliath. Saul dresses David in his armor, but they are too oversized for him. Instead, David retrieves smooth stones from a nearby riverbank and challenges Goliath to a fight, in which he kills Goliath slinging a stone to his forehead. Inspired by David's victory, the Israelites defeat the Philistine army.
Years later, David matures into a soldier in Saul's army, forming a strong friendship with Jonathan Mark Jacobson. Saul learns of a nearby Amalekite site, but when the Israelite army arrives, they find the Amalekites have left. Back in the palace, as David plays his lyre, Saul remembers the incident that made him lose his kingship, by disobedience to God for sparing the Amalekites to exploit despite being ordered to slay them. He realizes David is the prophesied King, and feeling betrayed, he throws a spear at David. Saul frames David for attempted murder, in which David flees for his life. When David is cornered, Jonathan fires an arrow at a construction site, knocking down a statue of Saul, inadvertently helping David escape.
Outraged, Saul and his army pursue David, killing those who assist him. David's family flee Bethlehem to escape persecution. He collapses in the wilderness, but is revived and takes shelter inside a cave. There, David is reunited with his family. Those inside are told of David's prophecy, but David insists he remains loyal to Saul. Meanwhile, Saul's army approach the cave. Dehydrated, Saul drinks from a waterfall inside. David decides to spare him and instead cuts a corner of Saul's robe, revealing himself to Saul, who forgives David and leaves.
David's family return to the Kingdom of Israel. Before long, the Philistines return to challenge the Israelites. David, his brother Eliab, and their warriors infiltrate the Philistine ranks to assist Saul and the Israelites. On the battlefield, they soon learn the Amalekites have attacked Ziklag, burned it, and taken the residents, including David's family, captive. As Saul and Jonathan are defeated by the Philistines, David and his warriors find that their families have been taken by the Amalekites, blaming David.
Faithful in God's deliverance, David approaches the Amalekites unarmed and is taken prisoner. As the Amalekite chieftain prepares to execute him, David begins to sing that he is unafraid, giving the Israelites the confidence to join in. His warriors arrive on the battlefield and liberate the Israelites. David recovers from the attempted execution shortly after, and the Israelites recognize him as their new King.
