They know his voice and will not respond to another. So it is with the people of God and the Good Shepherd. We can nurture a close relationship by fellowshipping with Him. In the tenth chapter of John, Jesus preached a beautiful sermon that described His role as the Good Shepherd. The only access into the kingdom of God is through Jesus Christ.
Every person has by birth a human nature that is sinful and spiritually rebellious.
In our unregenerate state we were selfish, willful, and carnally minded. In this state we could of never hoped to enter into the presence of God or be a partaker of the heavenly reward. Sin effectually had separated us from fellowship with our Creator. But in His great love the Good Shepherd provided Himself as a once and for all sacrifice for sins that a way of fellowship might be opened up to lost humanity. Faith in Christ moves a man to obey the plan of salvation that God has given in His word, and he is cleansed and regenerated by the power of Jesus Christ.