A weak, defenseless, thoughtless creature - and prone to wander!

(John Newton)

"I am the Good Shepherd. The Good Shepherd lays down His life for the sheep." John 10:11

This great and good Shepherd has a flock, whom He loved from everlasting - and whom having loved, He will love to the end. He . . .
  humbled Himself for their sakes,
  submitted to partake of their nature and their sorrows,
  took upon Him the form of a servant,
  and was made in the likeness of sinful flesh.

He died for His sheep, "the just for the unjust," to redeem them . . .
  from the curse of the law,
  from the guilt and dominion of sin,
  from the power of Satan - and to bring them to God.

They, by nature, are all "gone astray, every one to his own way". But having thus bought them with His blood - in His own appointed time He seeks, finds, and restores His sheep. By the power of His Word and Spirit - He makes Himself known to their hearts, causes them to hear and understand His voice, and guides them into His fold. They are under His immediate protection and government.

Considered as individuals, they are fitly described by the name of sheep. A sheep is a weak, defenseless, thoughtless creature - and prone to wander! If once gone astray - it is seldom known to return of its own accord.

A sheep has neither strength to fight with the wolf, nor speed to escape from him; nor has it the foresight of the ant, to provide its own sustenance.

Such is our character, and our situation -
  unable to take care of ourselves,
  prone to wander from our resting-place,
  exposed to enemies which we can neither withstand nor avoid,
  without resource in ourselves,
  and taught, by daily experience, the insufficiency of everything around us.

Yet, if this Shepherd is our Shepherd, as weak and helpless as we are - we may be of good courage. If we can say with David, "The Lord is my Shepherd" - then we may make the same inferences which he did, "Therefore I shall not want. Therefore I need not fear."

"My sheep listen to My voice; I know them, and they follow Me. I give them eternal life, and they shall never perish! No one can snatch them out of My hand!" John 10:27-28