Old Testament prophecies of the coming of the Messiah prepared people to think of Him as a Shepherd (Psalm 23; Isaiah 40:11; Ezekiel 34:11-16, 23; 37:24). In John 10:1, Jesus explains that the shepherd enters by the gate, the lawful way of going into a sheep pen as opposed to some other way. By this, He contrasts himself with false messiahs, who by deceitful claims seek to steal sheep or who presumptuously try to exert control over the people. Jesus Christ came as the legitimate Heir of the chosen seed and fulfilled the promises of the Old Testament.
Martin G. Collins
Parable of the Good Shepherd (Part One)
In the illustration many sheep are in an enclosure where several flocks come together for the night. The shepherd comes in the morning to lead them to their pasture, and he calls to his sheep by name. Though the individual flocks had become hopelessly intermixed during the night, the shepherd's sheep hear his voice and separate themselves from the larger flock.
Notice how often Christ emphasizes the voice of the shepherd in this short section: "The sheep hear his voice" (verse 3); "The sheep follow him, for they know his voice" (verse 4); "They do not know the voice of strangers" (verse 5). When the shepherd speaks, the sheep go to him immediately.
When "voice" is used in the New Testament, the writers all chose the Greek word phone, meaning "sound" or "spoken word." But phone can also mean "an address as to a group of people, a speech." Phone derives from phaino, meaning "to enlighten" or "to shine." From this root meaning springs the fact that phone can mean "disclosure" or "revelation" through an address or speech—a message!
This is its figurative meaning in John 10. The true and faithful shepherd will be preaching a message which his sheep will hear and immediately follow!
The Shepherd's Voice
The sheep, like the lover in Song of Songs 2:14, know the voice because they know the Shepherd and trust Him. They trust His voice. In it, they hear safety, security, sustenance, joy, hope, encouragement, love, warmth, and correction that does not turn them aside. The voice is the effective means of communication between Christ and us. The voice not only identifies, but it also communicates concepts to us that reveal both character and emotion.
John W. Ritenbaugh
Unity (Part 4)