The complete answer is found in 1 Samuel 17. Here one can read that the Philistines were encroaching upon Judean lands (verse 3). These Philistines put forth a 'champion' (a Hebrew expression for 'a go-between' or warrior who will fight a single combat as a stand-in for the entire armies). Now begins the great story of faith of David who had just defeated a lion and bear a short time before this and this probably gave him faith to trust God for victory over Goliath (Philistine champion).

We read in verse 45-47, that David would go before Goliath in the NAME OF THE LORD OF HOST, the God of the armies of Israel. Host here refers to God as Commander over the armies of heaven and Israel via the covenatal relationship with the Israelites. David was depending upon the power of God as the Warrior and Defender of His people as Exodus 15:3 states.

Now David as Israel's champion appeared as a shepherd boy chasing a dog or wolf away from his flock vis-a-vis Goliath who stood nearly 10 foot tall in full battle gear. Yet, in verse 48 we read how David hurried and ran toward the army to meet the Philistine. He took out a stone and slung it, striking Goliath in the forehead, killing him. Then David, not having a sword, took Goliath's sword and cut off his head. When the Philistines saw this improbable if not impossible outcome for their champion by the champion of Israel, they fled.

For instance the TV show Tom and Jerry, hence their height difference, considering that David and Goliath had a massive height difference as well.

Another one would be Sylvester Stallone's movie Rocky IVwhereas Sylvester, playing Rocky, is around 5' 9", fought a boxer from the Soviet Union named Ivan Drago. The actor who played as Ivan is Dolph Lundgren, who is around 6' 5".

The text only describes David as a youth. It doesn't give an age.

Answer:

Jesse had 8 sons (1 Sam 18:12). The oldest 3 were 20 years old and older according to Numbers 1:3. At the youngest, the 3 oldest sons would have been 22, 21, and 20 (unless they were triplets and all 20 years old). The 4th oldest son didn't serve in the army, which means at the oldest, he would have to be 19. That leaves the 5 sons who didn't join the military to be 19, 18, 17, 16, and 15 assuming that David's mother had 1 son a year. It's also a possibility that David had elder twin brothers, which would potentially make him older than 15.

The valley of Elah.

1 Samuel 17:19 : "Now Saul, and they, and all the men of Israel, were in the valley of Elah, fighting with the Philistines."

1 Samuel 17:19 says that Saul and all the men of Israel were in the valley of Elah, fighting the Philistines, then David offerred to fight Goliath, whom no one else dared face. However, there is biblical evidence that this was not a historical account. 2 Samuel 21:19 says that it was Elhanan who killed Goliath (Hebrew Bible in English [JPS 1917 Edition]* ): "And there was again war with the Philistines at Gob; and Elhanan the son of Jaare-oregim the Beth-lehemite slew Goliath the Gittite, the staff of whose spear was like a weaver's beam."

1 Chronicles, written later and apparently dependent on the Deuteronomist history, makes no mention of David killing Goliath, even though the Book of Kings presents this at the most important single feat leading to David being accepted as a potential king.

Footnote:

* The King James (KJV) translation amends 2 Samuel 21:19, adding "the brother of" (in italics to indicate that this was not an exact translation), but most other English translations seem to have continued with the Hebrew Bible version.

Millions of young children have been taught the famous story of the future King David slaying the Philistine giant, Goliath, to guide them to understand the greatness of David and, perhaps, his God, but the story is undoubtedly a myth.

The area, where Goliath and the other mythical giants of the Bible are supposed to have lived, is one of the most heavily worked archaeological region on earth, yet no skeletal remains of giants have ever been found. No huge residences in which a giant could have lived; no oversize pottery or eating implements; nothing.

The story's omissions from the Book of Chronicles could mean either that the story was unknown to the Chronicler or that he did not believe the story to be true. It is believed that the story may have been added to 1 Samuel after the Babylonian Exile, which is of course centuries after the time Davis is supposed to have fought Goliath.

The Bible makes no mention of the actual size of the stones in which David took to defeat Goliath. It only states that he took five stones from a brook. It is obvious that they could not have been too large, as they were used in a hand held sling.

1 Samuel also states that the stone itself is not the cause of Goliaths death but David instead slew Goliath using Goliaths own sword.

According to 1 Samuel 17: 49

David put his hand in his bag and took thence a stone, and slang it, and smote the Philistine in his forehead, that the stone sunk into his forehead; and he fell upon his face to the earth.

In the verse 51 it states that

David ran, and stood upon the Philistine and took his sword and drew it out of the sheath, and slew him, and cut off his head therewith.

Verse 51 clearly states that David actually "slew" (killed) Goliath with his own sword, the stone hit Goliath in the forehead cause him to fall and apparently knocked unconscious.

He couldn't walk in Saul's armor and with Saul's sword (Saul was quite tall, and David was still a young boy at the time). So he needed a) a weapon to use (because he couldn't use the sword) and b) preferably something with range (because he couldn't use the armor). So, since he had a sling, and was a pretty good shot with it from using it to scare predators away from the sheep.

Answer:

According to tradition, David was not a young boy (see 1 Samuel 16:18). He was in his twenties. Also, David did not kill the predators with his sling - he used his hands (1 Samuel 17:35). However, he was physically not a big man.

To address the question, the chief reason that David took nothing but a slingshot was to show his complete trust in God. The death of Goliath was a miracle in which God took part no less than did David.