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.
Davidiad
In Book IV, the Philistines attack the city of Keilah, and David repels their assault; however, when David discerns in prayer that the inhabitants of the city would turn him over to Saul, he flees into the Wilderness of Ziph. In time, the Ziphites approach Saul and promise to turn David over to him, but David escapes to the Wilderness of Maon. Saul initially gives chase, but his attention is diverted by a renewed Philistine invasion and David is able to secure some respite in a cave at Ein Gedi. After following the Philistines, Saul coincidentally journeys into the same cave. Given a chance to kill the king, David refuses; instead he secretly cuts off a corner of Saul's robe, and when Saul leaves the cave, he comes out to pay homage to Saul as the king and to demonstrate, using the piece of robe, that he holds no malice towards Saul. Moved by David's righteous, Saul and David are reconciled for the first time, and the former recognizes that the latter will indeed be the future king. Then, it is announced that Samuel has died. Afterwards, David journeys to the Desert of Paran, where he seeks provisions from Nabal, a rich man in the region. Nabal insults David, but Nabal's wife, Abigail, intervenes to avert David's wrath.