Jesus admits that sins are inevitable, but condemns those who tempt us to having millstones tied around their necks and being thrown into the sea. Then he tells us that if your brother sins seven times in the same day, you have to forgive him each time.
The apostles ask how they can increase their faith. He informs us that people with only a little faith can tell a sycamore tree to pick itself up and replant itself in the sea, and it will happen. G'head kids, try that one at home.
Then he starts talking about the proper treatment of slaves. How you can still have slaves if you've sold all your property and given the proceeds to the poor is not made clear. Anyway, most people don't invite their slaves to dinner after they've spent a long day in the field. Rather, they first make the slaves serve dinner, then dismiss them to their own suppers. They don't even think to say thank you. The disciples should think of themselves as the slaves here, and should do their tasks out of duty and not expect thanks.
That matter out of the way, they continue on towards Jerusalem. They pass 10 lepers who ask Jesus for some faith healing, so he obliges. One man follows along afterwards, praising god. Jesus asks where the other nine are, but doesn't get an answer. He dismisses the former leper.
Now the Pharisees have found him again, and they ask when heaven is coming. Jesus says you can't see heaven because it's inside you. What a rip-off! He turns to his disciples and completely changes his tune from what he said in Mark and Matthew about the End of Days happening within their lifetimes (because it didn't and this book was written 100-200 years after his 'death'), telling them that now they won't live to see his return. There will be lots of fake Jesus', just as there have been many Elvis sightings, but they'll know it's really him when there's a lot of lightening. Life will continue as normal, just like it did in Noah's and Lot's times, but then suddenly armageddon will start and only half of us can expect to live through it.