The sheep hear His voice and follow

But he who enters by the door is the shepherd of the sheep. To him the doorkeeper opens, and the sheep hear his voice; and he calls his own sheep by name and leads them out. And when he brings out his own sheep, he goes before them; and the sheep follow him, for they know his voice.
John 10:2-4 (NKJV)

My sheep hear My voice, and I know them, and they follow Me. 28 And I give them eternal life, and they shall never perish; neither shall anyone snatch them out of My hand.
John 10:27-28 (NKJV)