From the early Church Fathers to now.
“But Josue, and all Israel gave back, making as if they were afraid, and fleeing by the way of the wilderness.”
“But perhaps you say to me, "In what manner are the people in front placed as though fleeing?" In a most suitable manner. For truly, those who follow Jesus seem to flee from legal burdens and precepts, from the observation of the sabbath, from the circumcision of the flesh, and from cutting the throats of enemies. But on the other hand, the one who has followed Christ, the fulfillment and fullness of the law, does not flee.”
“But another thing occurs to me in this place as I consider Jesus [Joshua] fleeing before the face of the army of Ai. Why do you think it is that Jesus [Joshua] is described as fleeing? Let us consider whether perhaps there may be something that we may conquer by fleeing, and that there is some perfect virtue in flight. Paul the apostle teaches us saying, "Flee fornication." You see therefore that there is a certain "spirit of fornication" that we ought to flee, all who wish to remain chastely and piously and modestly in Christ. Thus this flight is that which holds salvation; this flight is of power; this flight confers blessedness. And not only must the spirit of fornication be fled, but in like manner, just as it is said, "Flee fornication," let us hear it said to us: "Flee wrath, flee avarice, flee greed and envy, flee detractions and slanders." Yet I do not know if anyone may flee these things; I do not know if anyone may escape them.Such was that army of Ai that Jesus [Joshua] instructed his soldiers to flee, and perhaps concerning these things he charged his disciples, saying, "If they persecute you in this city, flee into another one; but if in that one also, flee into another." For he wants us to flee from enemies of this kind; he wants us to be put out of reach of this kind of evil. If we are able in the meantime to escape the contagions of these evils by fleeing, then, seeing the devotion and intention of our heart, all those holy powers—those perhaps about which the apostle Paul says, "Are they not all ministering spirits sent into the ministry for the sake of those who will receive the inheritance of salvation?"9—who perhaps are holy angels who, seeing us exposed to pursuing demons, rise up against those who pursue us and, striking from behind, destroy them all. For Jesus is with those who are exposed to the ones pursuing, more than with those who follow after. And justly, because Jesus loves to be with those who flee fornication, those who flee pride, those who flee deceit, and those who flee falsehood.”
The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.