Christ’s sheep know His voice. A stranger’s voice is ignored because it is not recognized. This is discernment and discernment is acquired by frequent exposure to the Shepherd’s voice. After several exposures, His voice is easily recognized and other voices are ignored.
But he who enters by the door is a 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. When he puts forth all his own, he goes ahead of them, and the sheep follow him because they know his voice. A stranger they simply will not follow, but will flee from him, because they do not know the voice of strangers. John 10:2-5
Our problem is that our knowledge of good and evil has a loud and manipulative voice that can confuse. The constant good ideas and urge to act that the knowledge of good and evil produces are always busy. This manipulation can and will lose its power as the sheep learn to prefer the gentle call of the Shepherd. He leads them to pure water and fresh grass and the sheep find living nourishment.
In our practical experience, Christ’s voice comes to us through His still, small voice, His Word, our brothers and sisters in Him, and in other holy ways.