Some people think that if they did something beautiful yesterday, or last week, or even several years ago, they've done their part and G-d should continue paying them for it the rest of their life.
It's something like loaning money with interest --you lend it to someone last year and you're still making a profit off him today.
Problem is, the Torah prohibits charging interest--even from G-d.
If you did good yesterday, do twice as good today.
