Albert Barnes on John 10:27

My sheep. My church, my people, those who have the true spirit of my followers. The name is given to his people because it was an illustration which would be well understood in a country abounding in flocks. There is also a striking resemblance, which he proceeds to state, between them.

Hear my voice. See Jn 10:3,4. Applied to Christians, it means that they hear and obey his commandments.

I know them. See Jn 10:14.

They follow me. A flock follows its shepherd to pastures and streams, Jn 10:3. Christians not only obey Christ, but they imitate him; they go where his Spirit and providence lead them; they yield themselves to his guidance, and seek to be led by him. When Jesus was upon earth many of his disciples followed or attended him from place to place. Hence Christians are called his followers, and in Rev 14:4 they are described as "they that follow the Lamb."

(a) "My sheep hear my voice" Jn 10:4