This psalm was written by David, probably when he was a king. He had been a shepherd, and he was not ashamed of his former occupation.

— Charles Spurgeon

Psalm 23
The Lord is my shepherd; I shall not want.
He makes me lie down in green pastures.
He leads me beside still waters.
He restores my soul.
He leads me in paths of righteousness,
for his name's sake.
Even though I walk through the valley of the shadow of death,
I will fear no evil,
For you are with me;
Your rod and your staff,
They comfort me.

To his older brothers, David was young—possibly even a pest. To his father, Jesse, he was another one of his sons. To onlookers, he was a mere shepherd boy. But to God, David was the one destined to be king of Israel.

In 1 Samuel 16, God revealed to Samuel that He had rejected Saul as king and had chosen one of Jesse’s sons to be the replacement. Think of the list of qualifications that must have run through Samuel’s mind for such a position: tall, smart, articulate, brave, well-groomed, well-mannered, a natural-born leader. Samuel saw some of these characteristics in David’s brothers. But the Lord said to Samuel that He didn’t see it the same, because people look at the outward appearance, while He looks at the heart.

Samuel had Jesse call his sons together, yet Jesse didn’t call David in from tending the sheep. Was this an oversight? An assumption? A judgment call? A deliberate choice? After Samuel declined each of Jesse’s sons that were present, he asked, “Are these all your sons?” Imagine Jesse’s chagrin as he replied, “There is still the youngest, he is tending the sheep.”

Surely one who spent his time taking care of animals was not the one to take care of a nation, but as soon as Samuel saw David, he knew and David was anointed to become king. But it would be many years before David was to become king. What did he do after being anointed? Go to a refining school? Or to a government academy? Maybe military training? He went back out to the fields and continued to shepherd his flock. The king-to-be was doing lowly tasks. The future king’s character was being refined in the fields of everyday life to prepare him for his calling.

The true leader will have no desire to lord it over God’s heritage, but will be humble, gentle, self-sacrificing, and altogether as ready to follow as to lead, when the Spirit makes it clear that a wiser and more gifted man than himself has appeared

— A.W. Tozer