At the time of Jesus, it was taught (Mishnah Qidd 4.14) that “A man should not teach his son to be a herdsman…for their craft is the craft of robbers”. Shepherds weren’t seen as kindly old men. They were seen as crafty and thieves. But the Lord chose that figure to represent Himself and the Father- even though the Old Testament likens God to the shepherd of Israel. The startling, unsettling figure [for the first century Jewish mind] was to demonstrate how it is the Lord’s humanity that makes Him our saviour. Likewise, the likening of the Gospel to yeast would have been shocking; or to a mustard bush, which is a member of the cabbage family [rather, e.g., than to a fruitful vine or upright palm tree]. It is signaled to us that there is to be a strangeness to this new Kingdom about which Jesus spoke, a humanity and yet unusualness about it. It was hard for the Lord to explain to us the level of love for us which He would reach in the cross. So He told a story of a shepherd who so madly loves his sheep, whose life is so taken up by his job, that he would die to save one of them, and comes back triumphantly rejoicing when he has found the lost sheep (Lk. 15:5). The average shepherd would have surely accepted that some sheep are lost, it's the luck of the game. But this shepherd who dropped all and ran off after one lost sheep was no usual shepherd. And the element of unreality in the story brings out the Lord's grace towards us. Note in passing how the man : sheep relationship portrays that between us and Christ. As the sheep understood pathetically little about the shepherd's sacrifice to save it, so we too fail to appreciate the height of the fact that Christ died for us, as the shepherd for the sheep. We can be sure that the frightened sheep didn’t bob along on the shepherd’s shoulders, grinning all the way home. With his underside covered in faeces and mud, it would have struggled with the Saviour shepherd, fanatic almost in his passion to save the sheep. As he stumbled along the rocky paths, shoulders bowed down, hands against his chest clutching the animal’s paws, the shepherd would be the living imitation of the posture of the Lord as He carried the cross of our sins to Calvary. All this is a pattern of the almost fanatic effort we should expend to win back the lost.
And of course the element of unreality is seen in the way the shepherd takes the sheep home and not back to the fold, inviting neighbours around to rejoice that his sheep had been found. The quite unusual joy and humanly inappropriate love of the shepherd for that sheep is of course there to signpost to us the "love beyond all reason" of the true shepherd for us. The way the lost sheep is brought home rather than returned to the fold was also perhaps some sort of allusion to the teaching of Dt. 22:1 that the lost sheep of your brother's must be returned to him. This would mean that our pastoral care should not simply be for our 'own' sheep, those for whom we have responsibility; but for the lost sheep of other 'pastors' who've not done their job.
Jn. 10:12 implies that Christ, the good and fanatic shepherd, saw the wolf coming. He didn't flee, but fought with this ferocious beast until the death. He says that if He had not done this, the sheep would be scattered. The struggle between Christ and the devil / flesh was therefore at its most intense on the cross, in His time of dying. The cross was not only a continuation of His struggle with the (Biblical) devil. It was an especially intensified struggle; and the Lord foresaw this fight coming. There is an element of unreality in this story that serves to make two powerful points. Firstly, no normal shepherd would give his life in protecting his sheep. The near fanaticism of this shepherd is also found in Am. 8:4, which describes the Lord as taking out of the mouth of the lion the legs or piece of ear which remains of the slain sheep; such is the shepherd's desperate love for the animal that now is not. The love of Christ for us on the cross, the intensity and passion of it, is quite outside any human experience. Hence the command to copy His love is a new commandment. And secondly, wolves don't normally act in the way the story says. They will only fight like this when they are cornered, and they aren't so vicious. But the point the Lord is making is crucial to us: the devil, the power of sin, is far more powerful than we think, and the struggle against it on the cross was far far harder than we would think. For there He lived out the passion of the fanatic shepherd of His story.
This point about the strength of sin, and thereby the extent of the Lord’s victory, is brought out by another unreal element in the Lord’s picture of “a strong man fully armed [guarding] his own court” (Lk. 11:21 RV). This householder is fanatic; he wanders around fully armed to protect his own courtyard and his goods, rather than getting servants or guards to do it. The Lord being “stronger than he” through the cross was therefore indeed strong. The amazing extent and power of the Lord Jesus is further brought out in the story of the worker in the vineyard who can almost direct His boss- the Father- not to cut down the barren fig tree of Israel until it has more chance to bear spiritual fruit- “if not, then after that thou shalt cut it down” (Lk. 13:9). Speaking to crowds of day labourers and farm workers, this would have struck them as strange- that this worker had such power over his boss.
Not only is the shepherd unreal. The sheep are, too- once we perceive the link back to Ez. 34:17-22. They tread down the good pasture so others can't eat from it; having drunk clean water themselves, they make the rest of the water dirty by putting their feet in it; and the stronger sheep attack the weaker ones. This isn't how sheep usually behave! But these sheep are unusually badly behaved. And they are symbols of us, for whom this unusual shepherd gave His life.