The man who finds the treasure does not own the field, and so must sell his own goods for money to buy the field to get access to the treasure, which is hidden from everyone else.
The striking feature of the text is that it places all the emphasis on the treasure being hidden in a field. Its outward appearance is absent; it lies concealed in the lowly soil. It is precisely this hidden, humble condition of the treasure that Jesus wants to highlight. It also seems that the finder is not the owner of the field. Perhaps the story implies that he is a tenant or a steward. In that case, the treasure does not count as part of the field’s yield but belongs by right to the landowner, not to the one entitled only to its usufruct. The parable therefore takes us in a surprising direction: the finder does not purchase the treasure itself, but the field. An ordinary piece of land becomes worth everything, because the finder knows that within it lies the secret to a treasure that will transform his life. Whoever cannot be troubled to acquire the field will forfeit the wealth hidden within it.1
44 “The kingdom of heaven is like treasure hidden in a field, which a man found and covered up. Then in his joy he goes and sells all that he has and buys that field.