The tax collector and Pharisee

Luke
I find the parable of the Pharisee and the tax collector (see Luke 18:9-14) almost similar to the parable of the lost son.  The Pharisee is sort of close to God, in that he is always trying to do his duty and pray and all that, but he really doesn't understand God at all.  The tax collector has little regard for the law, has previously abandoned God, but realizes his need for God and repents from the depths of his heart.  He desires to get back to God.  The Pharisee is like the older brother in the parable of the lost son, and the tax collector is like the son who ran away from home.
The tax collector, as Jesus points out, is the one who God really listens to.  That doesn't mean that if you haven't committed terrible sins, God won't listen to you.  The point here is that we have to approach God with sincerity of heart and in humility.  That was the prayer of the tax collector, and that should be our prayer too.

One lost sheep

Luke
The parable of the lost sheep teaches that there is more rejoicing about the one lost sheep that is found than the other 99 who were saved already.  The earthly part of me wonders if God loves those recently lost but now found people more than the others.  That seems to be a reflection of our attitude toward lost things, which we think about more than all the possessions still safe in our homes.  The next series of parables are on this same idea of being lost.