The phrase starting with “Fear not, little flock” is unique to Luke. Paraphrasing Brant Pitre’s commentary on this it reflects what we also find in John’s Gospel regarding Jesus as the shepherd and his disciples as a flock. This builds on an image used by the Old Testament prophets. The little reflects a reality that only a portion or a remnant will be “will be righteous and obedient to God.” This reminds me of a 1969 broadcast on German Radio by then-Cardinal Ratzinger.
He references the “little flock” and also says:
From the crisis of today the Church of tomorrow will emerge — a Church that has lost much. She will become small and will have to start afresh more or less from the beginning.. … “The Church will be a more spiritual Church, not presuming upon a political mandate, flirting as little with the Left as with the Right. It will be hard going for the Church, for the process of crystallization and clarification will cost her much valuable energy. It will make her poor and cause her to become the Church of the meek. The process will be all the more arduous, for sectarian narrow-mindedness as well as pompous self-will will have to be shed. One may predict that all of this will take time.
Jesus then instructs them on almsgiving and the treasures that we should build up. If you can read the lines “For where your treasure is, there will your heart be also.” and not tremble a bit at them you are either oblivious, a liar, or on the path to sanctity.
St. John Chrysostom. For there is no sin which almsgiving does not avail to blot out. It is a salve adapted to ever wound. But almsgiving has to do not only with money, but with all matters also wherein man succours man, as when the physician heals, and the wise man gives counsel. 
“Jesus moves into discussing the active vigilance that should characterize the Christian life. The image of Passover lies in the background—the great liturgical vigil when Israel awaited the arrival of the LORD to take them away and betroth them to himself at Sinai. Thus the imagery of staying awake on a wedding night.””
The ESV-CE version uses “Stay dressed for action and keep your lamps burning,“ While we are used to the phrase of girding your loins, ”dressed for action” gives us the context here. Still, there is a deeper meaning in usage such as when Jesus girds himself with a towel and then he washes the feet of his disciples. That was a task of a slave to their master. The vigilance that is emphasized in this reading from the Gospel requires obedience and a relationship to Jesus if we are to be ready when the master arrives.
St. Gregory the 1st reflects:
The first watch then is the earliest time of our life, that is, childhood, the second youth and manhood, but the third represents old age. He then who is unwilling to watch in the first, let him keep even the second. And he who is unwilling in the second, let him not lose the remedies of the third watch, that he who has neglected conversion in childhood, may at least in the time of youth or old age recover himself.
The connected parables that Jesus uses to teach have four different outcomes.
- The first servant knows his master’s will and is vigilant until he returns. He is the one awarded the most.
- The second servant knew his master’s will but decided in the interim why he waiting for him to return decided to beat he could beat his fellow servants and eat and drink as if there was no judgment. This servant is cut in two. This is possibly a sign of breaking the covenant promises.
- The third servant also knows his master’s will, but he does not act on this. He is not as wicked as the second servant and is not living the epicurean life. His punishment is to receive a severe beating.
- The fourth servant does not know the master’s will but lives a life that deserves a beating as judgment. He is beaten lightly as he is in the category of what we now call “invincibly ignorant.”
Generally, it has been interpreted that the state of punishment after judgment refers to Purgatory.
John Bergsma writes:
In our Gospel passage, the varying degrees of punishment referred to, based on each one’s knowledge and therefore culpability, may refer either to hell or to purgatory. In any event, it teaches us that punishment in the afterlife will not be “one size fits all,” but the severity of punishment for wickedness in this life will be proportionate to the amount of revelation we have received. The spiritual tradition refers to this as being “judged according to one’s lights,” that is, according to the “light” (i.e., revelation, information received about God and salvation) each one experienced.
Between these four examples, Peter had asked “Lord, are you telling this parable for us or for all?”
John Bergsma ponders:
Is it just an accident that in response to _Peter’s_ question, the Lord begins to talk about a “faithful and prudent _steward_” who will be put in charge of all the servants? Matthew 16:18–19, when read in light of Isaiah 22:15–24, demonstrates that Jesus appointed Peter as the royal steward of his kingdom. For myself, I am convinced that this portion of Luke 12 is St. Luke’s equivalent of Matthew 16:18–19. It is the passage of his Gospel that lays out the Petrine role in the Church.
Jesus ends with:
But the one who did not know, and did what deserved a beating, will receive a light beating. Everyone to whom much was given, of him much will be required, and from him to whom they entrusted much, they will demand the more.
This is encapsulated in the phrase from Spider-Man “With great power comes great responsibility”, which was originally a caption and not spoken by any character.
As St. Augustine says:
“I’m terrified by what I am for you, [but] I am given comfort by what I am with you. For you I am a bishop, with you . . . I am a Christian. The first is the name of an office undertaken, the second a name of grace; that one means danger, this one salvation.”
And commenting on this passage in Luke, St. Ambrose writes:
“It seems to be set before priests, whereby they know that they will suffer severe punishment in the future, if, intent on worldly pleasure, they have neglected to govern the Lord’s household and the people entrusted to them.”
John Bergsma reflects:
How sobering, then, for those who are teachers, priests, superiors, professors, or other kinds of spiritual leaders! They have had so much education: woe be to them if they pervert what they have received! Thus Jesus says, “Whoever causes one of these little ones who believe in me to sin, it would be better for him if a great millstone were hung round his neck and he were thrown into the sea” (Mark 9:42, RSV2CE). It would be healthy to have a plaque made of this verse and have it hung in the theology departments of every Catholic school and university. Jesus had no encouragement or consolation to offer to authority figures who lead the young or the ignorant into committing sin. May none of us ever do such a thing.
Regardless, we are all called to vigilance, which results from growing in holiness.
The Vatican II document Lumen Gentium says:
“Since we know neither the day nor the hour, we should follow the advice of the Lord and watch constantly so that, when the single course of our earthly life is completed (cf. Heb 9:27), we may merit to enter with him into the marriage feast and be numbered among the blessed (cf. Mt 25:31–46) and not, like the wicked and slothful servants (cf. Mt 25:26), be ordered to depart into the eternal fire (cf. Mt 25:41)” 
From the Catechism, paragraph 2849:
Such a battle and such a victory become possible only through prayer. It is by his prayer that Jesus vanquishes the tempter, both at the outset of his public mission and in the ultimate struggle of his agony In this petition to our heavenly Father, Christ unites us to his battle and his agony. He urges us to vigilance of the heart in communion with his own. Vigilance is “custody of the heart,” and Jesus prayed for us to the Father: “Keep them in your name.” The Holy Spirit constantly seeks to awaken us to keep watch. Finally, this petition takes on all its dramatic meaning in relation to the last temptation of our earthly battle; it asks for final perseverance. “Lo, I am coming like a thief! Blessed is he who is awake.
- Catholic Productions, Commentaries by Brant Pitre
- 1969 Speech by Cardinal Razinger
- The Word of the Lord: Reflections on the Sunday Mass Readings for Year C – John Bergsma
- Lumen Gentium
- Catechism of the Catholic Church, 2nd Edition
- The Gospel of Luke, Catholic Commentary on Sacred Scripture, Rev. Pablo T. Gadenz
- Photo by Ben White on Unsplash
- Catholic Productions, Brant Pitre ↩
- St. John Chrysostom, Abp. of Constantinople, A.D.398. (Hom. 25. in Act.) Catena Aurea ↩
- S. Gregory I. Pope, A.D. 590. (ubi sup.), Catena Aurea ↩
- The Word of the Lord: Reflections on the Sunday Mass Readings for Year C, John Bergsma ↩
- Vatican II, Lumen gentium, 48, Nov 21, 1964 ↩
- Catholic Church. (2000). Catechism of the Catholic Church (2nd Ed). United States Catholic Conference. ↩