On Repayment

Western culture, specifically that of America, can be described in a number of ways.
For example, our diet is high in simple sugars and processed foodstuffs, with nutrients added as an afterthought which makes us fat.
We have pride in our free market allowing anyone with enough determination to get whatever he so desires, be it fame, fortune, or early retirement.
And we are also marked by our independence; self-reliance, if you will.

The emphasis on "self" is everywhere in our world.
just watch an Axe or alcohol commercial and you get a feel for the self-centeredness that we are encouraged to employ in our everyday thoughts and actions.

The religious leaders around the year 40 AD were some of the most self-centered men of the time. They would jump at any opportunity to promote themselves or flout their greatness. They announced their generosity as loudly and obnoxiously as they could so that the general populace was aware of their giving.
But one day, Jesus was having dinner at the house of one of these religious leaders.
To their snobbish behavior, he told his host and the other guests this:

"When you give a luncheon or dinner, do not invite your friends, your brothers or relatives, or your rich neighbors; if you do, they may invite you back and so you will be repaid. But when you give a banquet, invite the poor, the crippled, the lame, the blind, and you will be blessed. Although they cannot repay you, you will be repaid at the resurrection of the righteous." [luke 3:12-14]

It's a shame we don't know what Jesus' voice sounded like when he said this, but I imagine he had an air of sarcasm when he noted that their friends could pay them back.
He is suggesting that it is bad to be repaid for inviting people to hour houses- that we should avoid doing things that put others in debt to us, and on top of that, to purposefully bless people who can't bless us back.

In our world of high-powered business and sociopaths, people are often seen as having "good character" if they tend to do things mutually. That is, "i'll help you out, and you can help me out later on." rather than first asking for money for a deed or service. But we are told here to take it a step further.
We are told to only give to those who can't give back, who aren't capable of helping us out down the road.
After all, what does mankind benefit if everything is done for a fee?
It's just another example of investing in eternity, which is looking more and more appealing every day with the $700 billion bailout going on and such.