Parable is derived from the Greek word pronounced parabole, meaning a likeness or comparison. A parable is a method of teaching using a comparison between two things. Although it's quite natural to assume that Jesus Christ used parables to make His message clearer to everyone at that time, His very own explanation of His purpose in using them is somewhat of a surprise.
Why Did Jesus Use Parables?
In the Savior's own words:
"That same day Jesus went out of the house and sat beside the sea. And great crowds gathered about Him, so that He got into a boat and sat there; and the whole crowd stood on the beach."
"And He told them many things in parables, saying: "A sower went out to sow. And as he sowed, some seeds fell along the path, and the birds came and devoured them. Other seeds fell on rocky ground, where they had not much soil, and immediately they sprang up, since they had no depth of soil, but when the sun rose they were scorched; and since they had no root they withered away. Other seeds fell upon thorns, and the thorns grew up and choked them. Other seeds fell on good soil and brought forth grain, some a hundredfold, some sixty, some thirty. He who has ears, let him hear."
"Then the disciples came and said to Him, "Why do You speak to them in parables?"
"And He answered them, "To you it has been given to know the secrets of the kingdom of heaven, but to them it has not been given. For to him who has will more be given, and he will have abundance; but from him who has not, even what he has will be taken away. This is why I speak to them in parables, because seeing they do not see, and hearing they do not hear, nor do they understand. With them indeed is fulfilled the prophecy of Isaiah which says: 'You shall indeed hear but never understand, and you shall indeed see but never perceive. For this people's heart has grown dull, and their ears are heavy of hearing, and their eyes they have closed, lest they should perceive with their eyes, and hear with their ears, and understand with their heart, and turn for Me to heal them.'"
"But blessed are your eyes, for they see, and your ears, for they hear." (Matthew 13:1-16 RSV)
There is no favoritism with God (Romans 2:11), but He has chosen, throughout human history, according to His will, some as the "first fruits of salvation" (Romans 8:23), not because they were or are in any way better than anyone else, but to serve God, and the others, later (Revelation 20:6). That's the reason that there will be more than one resurrection (see Resurrections).
Fact Finder: While The Gospel will eventually be made known to all humanity, why was, and is, the true meaning of the Gospel revealed only to those "with ears to hear," some now, and the rest later?
See Ears To Hear