What comes before a parable really sets the scene for what story Jesus will tell.
Luke, Chapter 14, starts off with Jesus at the house of a Pharisee. Luke tells us that Jesus is "being carefully watched." The Pharisee clearly wanted to see Jesus up close and personal. If you invited someone to dine with you in the ancient world, you didn't just share a meal with the person, but you were extending the hand of friendship. I think the Pharisee may have mixed motives--he is curious about this person from Galilee who has swept the crowds off their feet. He is also deeply concerned that Jesus is running around blaspheming God every chance He gets--by claiming He is performing miracles, and telling those crowds of His intimate relationship with God.
Perhaps the invitation was given by one Pharisee and his guest list consisted of many other Pharisees, who who only came to "dine," and all the while they were watching Jesus like hawks.
First up: a miracle. A man who is swollen is present. Jesus asks the guest if it's OK to heal on the Sabbath; they don't say a word. Out in a bustling crowd, the Pharisees were able to make all kinds of comments about Jesus, perhaps out of earshot of Jesus and the person He was healing. But here, in this intimate setting, any comments they would make would be heard, so they remain silent. They are not willing to engage in any arguments that they view are beneath them; while they are not desirous to have the crowd behind them, they don't want to lose what little support they have by being overly mean and callous.
Jesus heals the man, answering His question with action. Then the meal is about to be served, and all the guests are jockeying for position. Do they want to be close to Jesus, to lean in and ask Him questions that they are eager to ask, but cannot do so in front of their peers? Do they want to sit next to this "prominent Pharisee" (Luke's word) and score some holiness brownie points in his company?
Whatever is happening, Jesus uses the opportunity to teach the people that humility is always the right move, because if you grab a seat that you are not to sit in, and you have to be asked to move by the host, you will be humiliated. Then He says, "For all those who exalt themselves will be humbled, and those who humble themselves will be exalted.”
That is Kingdom of God code for if you see the needs of others and step aside, God will see this and will invite you to sit with Him--for He is the ultimate Host.
Then, He turns to the host of the meal, and admonishes him to not to invite just his social circle, for he will be asked in kind, and so on, back and forth. That circle will be closed to anyone outside it. Instead, Jesus tells him to go out and invite those who cannot repay him: the blind, the lame, the weak and the poor. His reward will be when the graves open, the trumpet will sound and those who loved others will rise, clothed in righteousness.
"When one of those at the table with him heard this, he said to Jesus, 'Blessed is the one who will eat at the feast in the kingdom of God.'"
"Jesus replied: 'A certain man was preparing a great banquet and invited many guests. At the time of the banquet he sent his servant to tell those who had been invited, "Come, for everything is now ready."
'But they all alike began to make excuses. The first said, "I have just bought a field, and I must go and see it. Please excuse me."
'Another said, "I have just bought five yoke of oxen, and I’m on my way to try them out. Please excuse me."
'The servant came back and reported this to his master. Then the owner of the house became angry and ordered his servant, "Go out quickly into the streets and alleys of the town and bring in the poor, the crippled, the blind and the lame."
'"Sir," the servant said, "what you ordered has been done, but there is still room."
'Then the master told his servant, "Go out to the roads and country lanes and compel them to come in, so that my house will be full. I tell you, not one of those who were invited will get a taste of my banquet."