David
David was the youngest of eight sons who lived in Bethlehem. While a boy, he proved his courage by saving his father’s sheep from attack by a lion and a bear. While still a teen, David was chosen by the prophet Samuel to be a king (see 1 Samuel 16:12–13). At first, Samuel thought David’s older brother was the one whom God would choose because he was tall and well-built, but the Lord said to the prophet that it was the boy David who was to be made king. Samuel was told, “The Lord seeth not as man seeth; for man looketh on the outward appearance, but the Lord looketh on the heart” (1 Samuel 16:7).
After David was called to be the future king, the Philistines threaten to take it away. They bring in their biggest weapons (giants). Goliath of Gath was "six cubits and a span," being interpreted about 9ft 6in! Goliath defied God and challenged the Israelites that if anyone could kill him, the Philistines would be their servants, but if that warrior failed, then Israel would be slaves to the Philistine's. David, being the youngest took courage, denied all the armor and brought his sling and 5 stones.
1 Sam 17:46-49 " This day will the Lord adeliver thee into mine hand; and I will smite thee, and take thine head from thee; and I will give the carcases of the host of the Philistines this day unto the fowls of the air, and to the wild beasts of the earth; that all the earth may bknow that there is a God in Israel.
47 And all this assembly shall know that the Lord saveth not with sword and spear: for the abattle is the Lord’s, and he will give you into our hands.
When did the men and women of the Old Testament begin preparing for a lifetime of service to the Lord? From the scriptures we find that it was when they were young. When you are in your teens, you are old enough to learn about the Lord and do His will. As the prophet Alma said to his son Helaman, “O, remember, my son, and learn wisdom in thy youth; yea, learn in thy youth to keep the commandments of God” (Alma 37:35). Instead of waiting until you’re an adult, right now is the perfect time to start living a righteous life.