1 Samuel 17:1-23

Now the Philistines gathered their armies for battle; they were gathered
at Socoh, which belongs to Judah, and encamped between Socoh and Azekah,
in Ephes-dammim.  Saul and the Israelites gathered and encamped in the
valley of Elah, and formed ranks against the Philistines.  The Philistines
stood on the mountain on the one side, and Israel stood on the mountain on
the other side, with a valley between them.  And there came out from the
camp of the Philistines a champion named Goliath, of Gath, whose height
was six cubits and a span.  He had a helmet of bronze on his head, and he
was armed with a coat of mail; the weight of the coat was five thousand
shekels of bronze.  He had greaves of bronze on his legs and a javelin of
bronze slung between his shoulders.  The shaft of his spear was like a
weaver's beam, and his spear's head weighed six hundred shekels of iron;
and his shield-bearer went before him.  He stood and shouted to the ranks
of Israel, "Why have you come out to draw up for battle?  Am I not a
Philistine, and are you not servants of Saul?  Choose a man for
yourselves, and let him come down to me.  If he is able to fight with me
and kill me, then we will be your servants; but if I prevail against him
and kill him, then you shall be our servants and serve us."  And the
Philistine said, "Today I defy the ranks of Israel!  Give me a man, that
we may fight together."  When Saul and all Israel heard these words of the
Philistine, they were dismayed and greatly afraid.

Now David was the son of an Ephrathite of Bethlehem in Judah, named Jesse,
who had eight sons.  In the days of Saul the man was already old and
advanced in years.  The three eldest sons of Jesse had followed Saul to
the battle; the names of his three sons who went to the battle were Eliab
the firstborn, and next to him Abinadab, and the third Shammah.  David was
the youngest; the three eldest followed Saul, but David went back and
forth from Saul to feed his father's sheep at Bethlehem.  For forty days
the Philistine came forward and took his stand, morning and evening.

Jesse said to his son David, "Take for your brothers an ephah of this
parched grain and these ten loaves, and carry them quickly to the camp to
your brothers; also take these ten cheeses to the commander of their
thousand.  See how your brothers fare, and bring some token from them."

Now Saul, and they, and all the men of Israel, were in the valley of Elah,
fighting with the Philistines.  David rose early in the morning, left the
sheep with a keeper, took the provisions, and went as Jesse had commanded
him.  He came to the encampment as the army was going forth to the battle
line, shouting the war cry.  Israel and the Philistines drew up for
battle, army against army.  David left the things in charge of the keeper
of the baggage, ran to the ranks, and went and greeted his brothers.  As
he talked with them, the champion, the Philistine of Gath, Goliath by
name, came up out of the ranks of the Philistines, and spoke the same
words as before.  And David heard him.