What is the parables trying to teach us?

The parables in The Bible are about a number of topics. Usually the parables convey a spiritual truth.

Many of Jesus' parable were directed at the nation of Israel, through the parables Jesus showed the nation of Israel that they have departed from God's ways eg parable of the Lost Son, The Lost Coin

Some parables are about the kingdom of God eg The Sower, The Hidden Treasure.