Praise be Jesus and Mary, now and forever. 
In today's Gospel we see three aspects of Our Lord's life and ministry which can be summed up in three words. They are interaction, reaction, and request. First, we see Him interacting with the people in the cities and the villages, teaching and preaching and healing those who were graced to be in His presence. In His incarnation, God takes on our human nature. He becomes one of us, and He willingly and lovingly and generously interacts with us in order to bring true life and goodness into our lives. But along with Jesus's interaction, notice His reaction. St. Matthew says this, "At the sight of the crowds, Jesus's heart was moved with pity for them because they were troubled and abandoned like sheep without a shepherd," Matthew 9:36. Other translations will read, "He was moved with compassion."
The Greek word that's used there for compassion is very expressive. It's the word spalagnizomai. It means feeling compassion in your bowels, in your womb, or in your abdominal region, essentially in the depths of your soul with a bodily reverberation. The exact sense of the word is that Jesus had a visceral feeling of compassion for the people. As Father Simeon notes in his commentary, St. Matthew is giving us here a glimpse into the emotive and mental processes of Jesus. Essentially, we see a window into the heart of the Savior in those words. "He was moved with compassion for them." The secular Greek usage of that term, spalagnizomai, referred to someone who's courageous or demonstrating courage. The scriptural New Testament in Christian sense of that term, means to be tenderly merciful and compassionate, to display inner love and compassion and tenderness. Our Lord was not a Stoic at all. He was deeply moved by the distress and difficulties of the people. He had a deep emotional concern for them. He experienced the most intense feelings of tenderness, and empathy, and care. This is why He wept, for example, at the death of Lazarus in John 11:35, even though He knew He was going to raise Lazarus in a few minutes' time. Essentially, in St. Luke's Gospel, both the Good Samaritan and the father of the prodigal son are described as feeling and expressing that spalagnizomai, that sort of profound compassion.
Another way of looking at it is from a feminine perspective. It's like the heart of a mother that aches for their suffering child. It's not just an intellectual pity or a superficial sense of sorrow. No, it's like feeling or experiencing the wound that your child has. And even at times, experiencing it more deeply than they do. God says in Isaiah 49:15, "Can a mother forget her infant, be without tenderness for the child of her womb? Even should she forget, I will never forget you," says the Lord.
On top of that, you can even be suffering intensely because of the very bad spiritual or moral situation that a person is in, and they seemingly aren't suffering at all. Think of St. Monica, her years of agonizing over her son, St. Augustine, when he was living a very sinful life. Think of the mothers and fathers who anguish over their children's abandonment of the faith or their children's immoral lifestyles. And the children don't seem to be in any apparent difficulty whatsoever. Remember Our Lord's words in His prayer from the cross. He said, "Father, forgive them, they know not what they do," Luke 23:34. And He prayed this as they were raffling off His clothes, as we read in that same verse, too.
Sometimes our sufferings for other people are actually greater than what they themselves are experiencing. Our Lord is not content to share the truth and just heal the sick and the suffering. He identifies with them. He identifies with us. He sees our existential and spiritual situation very keenly, and it affects Him deeply. God takes in and takes upon Himself the full wounded reality of humanity and of each person. We should think about that a bit and reflect on it probably, and apply it to our own lives and our own struggles, too. Our Lord is moved with tender compassion when He looks upon you, very tender compassion. St. Matthew says that the people that Our Lord was encountering were troubled and abandoned like sheep without a shepherd, Matthew 9:36. Other translations say that the people were harassed and helpless or distressed and dejected, or cast aside, or dispirited, wearied, confused, worn out. One commentator says the literal sense of the text is that the people were mangled and cast aside like sheep who not only didn't have a shepherd to protect them, but who had just been torn apart by the wolves.
This is also a shot at the Pharisees and scribes, and religious leaders of the day, who shepherded themselves as the prophet Ezekiel had prophesied in Ezekiel 34. They cared about and they cared for themselves, not for God's people. And instead of caring for them and leading them to the Lord, they were actually acting as spiritual roadblocks. They blocked people from knowing and seeing and loving God and from living a good and holy life. It's strange how seemingly very religious people can do that, but they can, and sometimes they actually do. 
What's even worse, the Pharisees and the scribes worked to discredit Our Lord's ministry, and they accused the Savior of being in league with Satan. That's what they said in the first part of today's gospel. "He drives out demons by the prince of demons," Matthew 9:34.
It's heartbreaking when you think about it, to have a religious leader or a very supposedly spiritual person lead you further away from God. But it does happen. 
In the older commentaries, St. John Chrysostom said that not only did these men not improve the people's lot, but they also hindered their progress. St. Anselm said that though the people had shepherds, it was as though they didn't have them. St. Hilary, giving a bit of a different perspective in the fourth century, said that the people were harassed by the evil spirits, and they were helpless because, essentially, the Mosaic law couldn't save them. They needed a shepherd who could restore them to the guardianship of the Holy Spirit, said St. Hilary. 
So Our Lord's reaction to all this tells us volumes about God's concern and His care for us. He's not aloof. He's not the aloof watchmaker God. He's not emotionally impervious. He's not clinically detached. No, in Christ He cares deeply for our well-being.
So we move from interaction and reaction to request. Jesus says in Matthew 9:37-38, "The harvest is abundant, but the laborers are few. So ask the master of the harvest to send out laborers for his harvest." What we don't hear in today's gospel is actually the next verse of St. Matthew's gospel. The next verse is Matthew 10:1, where it says, “Jesus called to Himself His twelve disciples and gave them authority over unclean spirits to cast them out and to heal every disease and every infirmity.” So the request by Jesus to ask, to pray, the master of the harvest for laborers is actually first answered by Him, by His sending out the 12 to minister to others. Since Jesus is the master of the harvest, He shows His willingness and His eagerness to send laborers into His vineyard, laborers who will help His harassed and helpless sheep. 
Somewhat humorously, I imagine Our Lord saying that, "Pray the master of the harvest to send out laborers for his harvest." I imagine Our Lady hearing that and going over to Him and saying, "I think it's a great time to send out the 12. What do you think? I think you should do it now." She might have done that. I don't know. He can't refuse her anything. So then you hear in Matthew 10:1, and Jesus called to Himself the 12 and sent them out. Maybe that's how it played out. Who knows? 
But Jesus basically tells us to pray to Him, to ask Him to send out laborers, to send out shepherds who will shepherd His people according to His own heart. Pray for workers, Jesus tells us. Also, pray that you yourselves will be transformed into workers. So in our prayer for vocations, these are essentially the two things we're asking. One, an abundance of people who will answer the call to be humble and charitable, and generous priests and religious. And two, we're also implicitly asking Jesus to be God in us so that we can work more fruitfully in His vineyard and draw souls to Him. In short, the Lord doesn't give a clear, efficient 12-step program or plan of action to solve this problem of the harvest and the laborers. He simply says, "Pray to me, and I'll send more laborers to work for the conversion, sanctification, and salvation of souls." And I'll also make you one of those laborers by making your heart and your choices, and your decisions more like mine. 
Let's ask Our Lady for that grace that her Son would send more compassionate laborers into His harvest and that she would help us to become more like one of those people, more like the Good Samaritan, more like the father of the prodigal son, essentially more like God Himself in His dealings with us. 
Praised be Jesus and Mary, now and forever.