Maimonides wrote in his essay called Chelek that people who think that what midrashim say is true are fools, those who reject them out of hand because they are not true are also fools; people need to realize that the rabbis wrote midrashim as teaching tools, as parables to teach Jews how to behave.
The following are imaginative generally unrealistic interpretations that I mention in my latest book “Who Really was the Biblical David.” None of the following ideas are in the book of Samuel.
- God awarded Orpah the sister-in-law of Ruth with giants as descendants because of the forty steps with which she accompanied her mother-in-law Naomi when Naomi returned to Judea from Moab. There were four brothers and Goliath was one of them. He merited the ability to show his strength to the Israelites during the days of Saul for forty days, the number of steps.
- David’s father encouraged David to help Saul, a Benjamite, because David was a descendant of Judah, son of the patriarch Jacob, and in Genesis Judah tried to protect Saul’s ancestor Benjamin, so a descendant of Judah should do it again.
- David did not pick up the five pebbles, they came to him. The five joined together and became one. When Goliath saw David, he was so impressed that he became leprous.
- Saul was afraid to fight Goliath because God took the divine spirit from him. Goliath came and threatened the Israelites in the morning and evening when the prayer Shema was usually recited, to confuse them and stop them from reciting it so that God would not help them. Goliath was the son of one woman and a hundred lovers; she was a prostitute. Orpah merited to have giants because she cried when she left Naomi.
- Goliath frightened the Israelites when he said, don’t be amazed at my height; all Philistines are as tall as me.
- David was 28 years old when he fought Goliath. Goliath did not fall back when struck with the stone. God told an angel to push Goliath forward so that the righteous David would not have to walk far. David took Goliath’s head on a tour of Israel to show the nation what God helped him do.
 Ginzberg, The Legends of the Jews.
 Babylonian Talmud, Sotah 42a.
 Rabbi Nosson Scherman, ed., The Rubin Edition of the Prophets: Samuel I and II (New York: Mesorah Publications, 2002).