1 Samuel 17: 40 And he took his staff in his hand, and chose him five smooth stones out of the brook, and put them in a shepherd's bag which he had, even in a bag; and his sling was in his hand: and he drew near to the Philistine.

David Fought With Weapons He Knew

David refused Saul’s armor, helmet and sword because he was not a soldier and had not used these weapons of warfare before. “I cannot go with these for I have not tested them.” He was unfamiliar with those weapons. Instead he took the weapons he was familiar with a shepherds rod and a sling. Didn’t seem like much against a giant whose armor weighed more than he did, but they were the weapons David knew and has used many times before.

David then stoops down by the stream between the two mountains and picks up 5 smooth stones. These stones had been tumbled by the stream for years until they were smooth and as near to round as possible. The smoother and rounder the stone, the more it would fly straight at its target.

In the Old Testament and even up to the time of the Romans a sling was a powerful weapon. Most times it was used like artillery, the slingers would stand at the back of the army and sling their stones so they fell like a hailstorm upon the heads of the approaching army. The stone could be as big as baseballs when slung as artillery. The Romans made sling stones out of lead and shaped them like acorns so that as they flew through the air they would whistle and distract the enemy as they charges.

The Bible talks about the 700 Benjamites who were so skilled as slingers that they could use the right or left hand and “could sling stones at a hair breadth, and not miss” (Judg. 20:16; 1 Chr. 12:2). That kind of slinging would require as round and smooth a stone as David had collected from the stream. These weren’t for an artillery barrage they were for sharp shooting.

Then the Bible says, “and his sling was in his hand: and he drew near to the Philistine. His preparation was over, he had the weapons he knew how to use and the five stones that he knew would fly the straightest. He then walked right toward that almost 10 ft tall giant.
 
Fight With Weapons You Know

Our weapon of spiritual warfare is the Bible. This is our sling. You better be familiar with it use. Not only read it, but study it, memorize it and be able to navigate it correctly. You can’t win the battle if you don’t know how to handle the weapon the Lord gave you.

Paul tells us in Ephesians 6:17 And take the helmet of salvation, and the sword of the Spirit, which is the word of God:

In Hebrews 4:12 we read, “For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart.”

The Word of God is the Sword of the Spirit and you need to know how to wield it in battle or you will lose the battle.

Five Smooth Stones to pick up and use. Let me give you 5 smooth stones that you need to have prepared before you go into those spiritual battles.

The Cornerstone of the Savior

Ephesians 2:20 And are built upon the foundation of the apostles and prophets, Jesus Christ himself being the chief corner stone.  

You better have Jesus the chief-stone in your arsenal. You won’t win with unless you are built up on Him as cornerstone of your life. The cornerstone determines the beginning, and the boundaries of a building and Jesus is your cornerstone. You better know your saved by grace through faith. You better know that salvation is eternal and cannot be earned nor lost. You better know how Jesus wants you to live your life. For if you don’t possess this stone, then you have no hope to win the battle of eternity or any of the battles of life that come before eternity.

Stone of Supplication.  
Paul tells us in 1Thess 5:17  Pray without ceasing. Jesus tells us that Men ought always to pray and not to faint.”

You need to have experience in prayer and its power. If you don’t know how to pray, personally, intimately, and desperately to the Lord then you can’t win spiritual battles.

Stone of the Gospel
The battle for eternity is fought with the story of Jesus death and resurrection. He said, John 12:32 And I, if I be lifted up from the earth, will draw all men unto me.
 
It not about your words, your eloquence or your powers of speech, its about the One who was lifted up on the cross and died for all mankind.

If you really want to win the battle for the souls of men then you must know and tell the story of Jesus coming, living, dying and risen again. He is the rock that either falls on us in judgment or we fall on Him in repentance.

Stone of Hope
You have to have hope in your sheperds bag and you have to be able to launch hope to those who have not experienced it through Jesus Christ.

Romans 5:1-5 Therefore being justified by faith, we have peace with God through our Lord Jesus Christ: By whom also we have access by faith into this grace wherein we stand, and rejoice in hope of the glory of God. And not only so, but we glory in tribulations also: knowing that tribulation worketh patience; And patience, experience; and experience, hope: And hope maketh not ashamed; because the love of God is shed abroad in our hearts by the Holy Ghost which is given unto us.

Stone of Sacrifice
This stone in your shepherd’s bag means you are willing to give all to Christ and to give up all for Christ.
 
Philippians 3:7-10 But what things were gain to me, those I counted loss for Christ. Yea doubtless, and I count all things but loss for the excellency of the knowledge of Christ Jesus my Lord: for whom I have suffered the loss of all things, and do count them but dung, that I may win Christ, And be found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith: That I may know him, and the power of his resurrection, and the fellowship of his sufferings, being made conformable unto his death;

There are many other stones in your Bible just as there were many other stones in the stream when David chose his five, the main point it that you pick them up and know how to use them effectaviely in your own life battles and in the other’s battles of life and eternity.