Why did the Lord teach in Parables?

In the bible dictionary we learn that Jesus taught in parables and that "without a parable spake he not unto them" (Mark 4:34)  There must be a very significant reason why he would choose this method of teaching. It Matthew 13:35 the Lord said, "That it might be fulfilled which was spoken by the prophet, saying, I will open my mouth in parables; I will utter things which have been kept secret from the foundation of the world."  In the bible dictionary it says, "It was to veil the meaning. The parable conveys to the hearer religious truth exactly in proportion to his faith and intelligence; to the dull and uninspired it is a mere story." If we are spiritually prepared when we read the scriptures or listen to the words of the prophets, we will be able to understand what the Lord would have us learn.  Only he who seeks shall find.  

In my New Testament class we did the following research on different parables that the Lord taught.  

                                                                                        

1. In the Bible Dictionary, read the first three paragraphs under the entry “Parables” (pp. 740–41).
2. Read the following parables: parable of the tares (Matthew 13:24–30); parables of the mustard seed and the leaven (Matthew 13:31–33); parables of the treasure and the pearl of great price (Matthew 13:44–46); parable of the gospel net (Matthew 13:47–50). Next to each of the following questions match the name of the parable that best answers that question.
• What describes the future growth of The Church of Jesus Christ of Latter-day Saints? Leaven
• Why does the Church send out so many missionaries? Net
• How do you explain the remarkable growth of the Church, considering that it is fairly new compared to most world religions and started small in the American frontier? Mustard
• Why are some members of the Church willing to sacrifice so much worldly wealth and recognition in order to maintain membership in the Church? Treasure, Pearl
• Why do some Church members choose to leave the Church? Tares
3. Address the following questions:
• Considering the parables of the treasure and the pearl of great price (see Mattthew 13:44–46), what sacrifices would you be willing to make to obtain the treasure of the gospel? What sacrifices have you or those you know already made for the gospel? Both my parents are converts and sacrificed family relationships and word of wisdom habits.  I don’t feel like I have sacrificed much because I consider everything I do with the gospel a blessing.  I guess I sacrifice my time as I serve in the Relief Society but it really doesn't feel like a sacrifice.  I know that it's important for me to stay home with my children and so I do sacrifice having some of the worldly things like a nice house and car so that we can afford for me to stay home.  
• What does the net represent in the parable of the net cast into the sea? (See Matthew 13:47). What does it mean to be gathered into the net? Missionaries. What is represented by the action of gathering the good into vessels and casting the bad away? Final Judgment (See Matthew 13:48–50).