The disciples ask Jesus who is the fairest of them all in heaven. Jesus, ever theatrical, brings in a kid to answer Except ye be converted, and become as little children, ye shall not enter into the kingdom of heaven. (v. 4)
Then he starts talking about who is going to heaven and who is going to hell. He repeats the bit about plucking out your eyes, and adds that hands and feet are also fair game. He also advises being nice to everyone, since you never know what disguise god is using today.
Next he has some instructions for what to do when your brother is being a dick: first, talk to him privately, but if he won't listen, gather some witnesses. If not even that works, put it before your church's congregation. If he ignores even that, you can write him off.
Jesus is really into consensus in this chapter, and promises that if two people on earth want something, god will make it so. G'head. Try that one at home with your family. Ask for a million bucks, or if you're the kids and your dad says you can't have a dog because they're smelly and he'll be the one who ends up taking care of it, pray to god to send you one.
Peter isn't satisfied with this loosey-goosey forgive thy brother crap. He wants statistics: how many times do you have to do it before you can write him off completely? Seven? Oh, no. You have to be one tolerant sumbitch I say not unto thee, Until seven times: but, Until seventy times seven. (v. 22) Now, I'm sure I've forgiven my brother more times than that, but his sins mostly consist of hogging the remote control.
To illustrate, he starts on the story of a king who discovers that he's loaned his slave One Million Dollars, which just strikes me as incredibly poor judgement. How is your slave, with no income or property, ever supposed to pay you back? The king also sees this problem and commands that the servant and his family be sold as repayment. The slave begs for forgiveness and promises he's good for every penny of it. The king stupidly lets him go. The slave immediately goes to another slave who owes him a hundred pence, takes him by the throat, and demands repayment. This second slave tries the Dumb and Dumber trick, but the first slave is clearly smarter than the king, if not a genius, and throws him into prison. The other slaves tell the king, who has the first slave tortured.
So what is Jesus' grand unifying message here? Slavery is soul-destroying? Don't torture people because it's evil? Subprime loans will destroy the entire planet's economy for at least 4 years? No, forgive your brother.