Let us then be shepherds like the Lord. We must meditate on the Gospel, and as we see in this mirror the example of zeal and loving kindness, we should become thoroughly schooled in these virtues.
For there, obscurely, in the form of a parable, we see a shepherd who had a hundred sheep. When one of them was separated from the flock and lost its way, that shepherd did not remain with the sheep who kept together at pasture. No, he went off to look for the stray. He crossed many valleys and thickets, he climbed great and towering mountains, he spent much time and labour in wandering through solitary places until at last he found his sheep.
When he found it, he did not chastise it; he did not use rough blows to drive it back, but gently placed it on his own shoulders and carried it back to the flock. He took greater joy in this one sheep, lost and found, than in all the others.
Let us look more closely at the hidden meaning of this parable. The sheep is more than a sheep, the shepherd more than a shepherd. They are examples enshrining holy truths. They teach us that we should not look on men as lost or beyond hope; we should not abandon them when they are in danger or be slow to come to their help. When they turn away from the right path and wander, we must lead them back, and rejoice at their return, welcoming them back into the company of those who lead good and holy lives.
From a homily by Saint Asterius of Amasea, bishop 410AD