The Lord taught in Matthew 13:44 - "Again, the kingdom of heaven is like treasure hidden in a field, which a man found and hid; and for joy over it he goes and sells all that he has and buys that field."
In Jesus' day there were no banks in which one could safely deposit his money. Thus, to prevent thieves from stealing it, men would often bury their treasure in a field. The problem with hiding one's treasure in this manner is that the sudden death of the one who buried the treasure would often result in the loss of all knowledge regarding the treasure's location. This parable is describing a situation of this sort (i.e., the current owner of the field is apparently ignorant that there is a treasure on his property). Technically, the treasure belonged to the owner of the field, but for all practical purposes it belonged to the man who found it. The finder conceals the treasure until he has purchased the field for himself.
This parable does not condone the man's dishonesty in hiding the treasure again and failing to disclose it to the owner of the field. Jesus occasionally referred to certain things that were unrighteous to illustrate His points (e.g., Matt. 24:43; Luke 16:8). The point here is that this man recognized the value of what he had found. He gladly and eagerly sold everything else he had in order to possess that treasure. The spiritual application is this: the kingdom of heaven is more valuable than any treasure man can imagine! Once the truth of God's kingdom is found, no sacrifice should be considered too great in obtaining it. One must be willing to give up sinful habits, illicit relationships, immoral occupations, and even family relationships that are spiritually destructive (cf. Luke 14:33).
Jesus delivered the second parable in Matthew 13:45,46 - "Again, the kingdom of heaven is like a merchant seeking beautiful pearls, who, when he had found one pearl of great price went and sold all that he had and bought it."
This parable is very similar to the one preceding it in that once the "treasure" is found (i.e., a unique pearl of tremendous value), then everything else is considered expendable by comparison. One minor difference between these two parables is that in the previous one the treasure appears to have been found by accident. In this parable, however, the man was searching for "pearls" all along. It is certainly true that some will find the kingdom without searching for it (e.g., John 4; Acts 2), but others will not find it until after much diligent searching (e.g., Acts 10).
Dear friends, are you searching for true, lasting riches? You will only find them in the gospel message and God's kingdom (i.e., the church). Spiritual treasures are the only kind that really matter because they are the only type that endure beyond this life. Examine your life and make sure your heart is in the right place and that you are really seeking the best treasure (cf. Matt. 6:19ff). Only a fool would reject an incorruptible spiritual treasure of priceless value to embrace a temporal treasure of infinitely less value.