Summary: It is interesting that David, who was an experienced shepherd, pictured himself as a sheep, not a shepherd.
Purpose: To show that God is a good and tender shepherd.
Aim: I want the listener to grasp a deep confidence in God’s goodness.
INTRODUCTION: It is interesting to note that sheep are the most commonly mentioned animal in the Bible. When you include the term "flocks" there are over 400 times the Bible refers to sheep. The word shepherd is also used over 100 times.
It was natural for David to talk about shepherds because he was one. David knew all about sheep. It is interesting that David, who was an experienced shepherd, pictured himself as a sheep, not a shepherd.
In our part of the world sheep are mostly raised for their meat. In Bible days, though, they were primarily raised for their wool and milk. For that reason it was not uncommon for shepherds to be with the same sheep twenty four hours a day for ten years or more. This made it possible for shepherds to develop deep personal relationships with their sheep.
I think this helps us understand why angels chose to announce the birth of Christ to shepherds.
In order to understand the importance of the eternal God being our refuge we must first ask:
► I. What are Sheep Like?
► Vs.1 A. Sheep are needy "want"
Sheep have actually been known to nibble themselves over the cliff! That is dumb! Dogs can often find their way home but not sheep. We laugh until we realize that "sheep" are a metaphor for us! So what do we need more than anything else? Clearly we need a tender, caring shepherd who is willing to take care of us.
► Vs.2a B. Sheep are restless "lie down"
"’pastures of tender grass,’ are mentioned, not in respect to food, but as places of cool and refreshing rest." 
When life gets difficult we get frantic.
► Vs.2b C. Sheep are weary "quiet waters"
Sheep drown easily. Their wool soaks up water and can drag them down. If they get on their backs they cannot get back up. They can only kick & bleat.
We need protection from the swirling torrents of this life.
► Vs.3a D. Sheep are sinful "restores my soul"
The Lord provides forgiveness and peace for those who follow Him.
Paul explains that apart from Christ we are helpless, ungodly, sinners, and enemies of God (Romans 5:6-10).
O death, O grave, I do not fear your power;
The debt is paid.
On Jesus in that dark and dreadful hour
Our sins were laid.
--Margaret L. Carson
► Vs.3b E. Sheep are lost "guides me"
Webster’s definition for "sheep" is interesting: "a timid and defenseless creature." In blunt terms they are dumb. By the way, you will never find sheep acts in the circus because they can’t be trained.
Sheep don’t learn from mistakes. In fact they often repeat them. When they wander away and get lost they often can’t even find their way home even when the sheepfold is within sight! Now that is helpless!
Isaiah 53:6 All of us like sheep have gone astray, Each of us has turned to his own way; But the Lord has caused the iniquity of us all To fall on Him. (NAU)
Psalm 119:176 I have gone astray like a lost sheep; seek Your servant, For I do not forget Your commandments. (NAU)
► Vs.4 F. Sheep are fearful "fear no evil"
Psalm 46:1--5 God is our refuge and strength, A very present help in trouble. Therefore we will not fear, though the earth should change And though the mountains slip into the heart of the sea; Though its waters roar and foam, Though the mountains quake at its swelling pride. Selah. There is a river whose streams make glad the city of God, The holy dwelling places of the Most High. God is in the midst of her, she will not be moved; God will help her when morning dawns. (NAU)
► II. What is Jehovah-Rohi (The LORD my Shepherd) Like?
► Vs.1 A. The LORD my Shepherd supplies my every need "I shall not want"
Notice the future tense: "I shall not..." David is NOT just saying "I don’t lack anything." He is saying, "I will not lack anything tomorrow." If you are trusting the Eternally Self-existent One to be your Shepherd then you will have confidence that tomorrow’s needs will be met.
Isn’t that what Paul said? Philippians 4:19 And my God will supply all your needs according to His riches in glory in Christ Jesus. (NAU)
John Walvoord writes that... "Sheep are utterly dependent upon the shepherd for almost everything pertaining to their well-being. In the work of Christ for His sheep, there is accordingly the ministry of leading the sheep in the path of the will of God. Only as sheep are willing to follow Christ will they find their complete spiritual needs supplied."