7 We have seen who the hireling is also. Who, but the devil, is the wolf? And what was said of the hireling? “When he sees the wolf coming, he flees: but the sheep are not his own, and he cares not for the sheep.” Was the Apostle Paul such an one? Certainly not. Was Peter such an one? Far from it. Was such the character of the other apostles, save Judas, the son of perdition? Surely not. Were they shepherds then? Certainly they were. And how is there one Shepherd? I have already said they were shepherds, because members of the Shepherd.
In that head they rejoiced, under that head they were in harmony together, with one spirit they lived in the bond of one body; and therefore belonged all of them to the one Shepherd. If, then, they were shepherds, and not hirelings, wherefore fled they when suffering persecution? Explain it to us, O Lord. In an epistle, I have seen Paul fleeing: he was let down by the wall in a basket, to escape the hands of his persecutor. Had he, then, no care of the sheep, whom he thus abandoned at the approach of the wolf?
Clearly he had, but he commended them by his prayers to the Shepherd who was sitting in heaven; and for their advantage he preserved himself by flight, as he says in a certain place, “To abide in the flesh is needful for you.” For all had heard from the Shepherd Himself, “If they persecute you in one city, flee ye into another.” May the Lord be pleased to explain to us this point! Lord, You said to those whom Thou certainly wished to be faithful shepherds, and whom You formed into Your own members, “If they persecute you, flee.”
Doest Thou, then, injustice to them, when Thou blamest the hirelings who flee when they see the wolf coming! We ask You to tell us what meaning lies hid in the depths of the question. Let us knock, and the keeper of the door, which is Christ, will be here to reveal Himself.
Source: Tractates on the Gospel of John (New Advent)