My sheep hear My voice, and I know them, and they follow Me.
The apostle Paul taught the Ephesians that one of the functions of the church is to build up the people in “the knowledge of the Son of God” (4:13). The word knowledge refers to full knowledge that is correct and accurate. That is the knowing of which Jesus spoke in today’s verse. He was not speaking of merely knowing their identities but of knowing them intimately, and that is the way He wants His people to know Him.
Paul’s desire is for every believer to develop this deep knowledge of Christ by building a relationship with Him through prayer and faithful study of and obedience to God’s Word. Growing in this deeper knowledge of Christ is a lifelong process that will not be complete until we see the Lord face–to–face.
10:27 These next few verses teach in unmistakable terms that no true sheep of Christ will ever perish. The eternal security of the believer is a glorious fact. Those who are true sheep of Christ hear His voice. They hear it when the gospel is preached, and they respond by believing on Him. Thereafter, they hear His voice day by day and obey His Word. The Lord Jesus knows His sheep. He knows each one by name. Not even one will escape His attention. No one could be lost through an oversight or carelessness on His part. Christ’s sheep follow Him, first by exercising saving faith in Him, then by walking with Him in obedience.
27 Three things are true of Jesus’ flock: they listen to his voice, they are known by him, and they habitually follow (present tense) him.
Repeating what He said in His discourse on the Good Shepherd (see the exposition of vv. 3–5 in the previous chapter of this volume), Jesus said, “My sheep hear My voice, and I know them, and they follow Me.” The elect will heed Christ’s call to salvation and continue in faith and obedience to eternal glory (cf. Rom. 8:29–30). 
 MacArthur, J. (2001). Truth for today : a daily touch of God’s grace (p. 140). Nashville, Tenn.: J. Countryman.
 MacDonald, W. (1995). Believer’s Bible Commentary: Old and New Testaments. (A. Farstad, Ed.) (p. 1527). Nashville: Thomas Nelson.
 Mounce, R. H. (2007). John. In T. Longman III & D. E. Garland (Eds.), The Expositor’s Bible Commentary: Luke–Acts (Revised Edition) (Vol. 10, p. 507). Grand Rapids, MI: Zondervan.
 MacArthur, J. F., Jr. (2006). John 1–11 (p. 442). Chicago: Moody Press.