My sheep hear my voice and I know them and they follow me.
And he added,
And I give them life everlasting and no man shall pluck them out of my hand.
But how do we hear Christ's voice? After all, it's many centuries since he preached in Galilee and Jerusalem. Clearly we don't hear his literal or 'physical' voice. He is in heaven and we live on earth. So how must we hear our Lord's voice in order to reach everlasting life?
Jesus himself showed us how to understand his words when he told the apostles on another occasion,
He who hears you hears me.
The voice of the Good Shepherd is an eminently powerful one. It passes from Christ to his apostles, and from them to their successors, and so on even to our own day. It may seem at times to be drowned out by a babble of competing noises, but it can never be entirely silenced. We know this, because Christ has promised:
I am with you all days, even to the consummation of the world.
And the faithful, 'the flock that is led by his hand', hear this divine voice. All baptized and confirmed Catholics receive from God a 'spiritual instinct' by which they recognize Christ's voice speaking through the pastors of the Church. Unless they deaden this instinct by continually acting against their conscience, it will guide them safely to the pastures of eternal life.
Sometimes they need this instinct to help them distinguish the faithful shepherd from the hireling. The faithful shepherd is the one in whom the faithful can hear Christ's voice; the hireling speaks with his own voice. The faithful shepherd preaches only what he has himself received, from preceding generations, from the apostles and ultimately from Christ himself. The hireling preaches a message adapted to the 'spirit of the age'.
In the fourth century a great storm broke upon the Church -- what is called the Arian crisis. Arius was an Egyptian priest who denied that Christ was truly God. His preaching spread and infected numerous other priests, and very many bishops, until the pope himself became afraid to profess the true faith.
The faithful were confused; they could no longer discern the voice of the Good Shepherd in the preaching of their pastors. Only a few shepherds, such as St Athanasius and St Hilary, remained firm. And the sheep recognized in their preaching the voice of Christ, and they followed them.
Today the flock faces a threat which is different, yet strangely parallel. It is not the divinity of our Lord which is put in doubt, but the 'divinity' of the Catholic Church. Obviously, the Church is not the incarnation of a divine person, but she can be called 'divine' insofar as she was founded directly by God, and is the society in which human beings are united to God. In this she is unique. So in the Song of Songs, the Son of God says of her:
One is my dove, my perfect one is but one.
Our Lord is the one mediator between God and men, and the Church is the Body of him who thus unites heaven and earth. This is why the path to heaven comes only from Christ through the Church which is his Body.
The Bible shows us in many places that in order to hear the voice of the Good Shepherd, intelligence is not enough. In fact, natural intelligence counts for very little.
When St Paul and St Barnabas preached at the synagogue in Antioch, some of the Jews accepted their message and some rejected it. There is nothing in the Acts of the Apostles to suggest that those who rejected it were less intelligent, less well informed or even (humanly speaking) less well versed in the Scriptures than the others.
Why then did they not believe? It was because they did not have enough love for the truth.
Jesus himself said to Pilate:
Everyone that is of the truth hears my voice.
If we wish to hear the voice of our Good Shepherd we must love the truth. Only the Holy Spirit, the 'promise of the Father', can make us do this enough. Veni, Sancte Spiritus!