Origen's Commentary on the Gospel of Matthew

And at this point you will inquire, whether the kingdom of heaven is likened only to the treasure hidden in the field, so that we are to think of the field as different from the kingdom, or is likened to the whole of this treasure hidden in the field, so that the kingdom of heaven contains according to the similitude both the field and the treasure hidden in the field. Now a man who comes to the field, whether to the Scriptures or to the Christ who is constituted both from things manifest and from things hidden, finds the hidden treasure of wisdom whether in Christ or in the Scriptures. For, going round to visit the field and searching the Scriptures and seeking to understand the Christ, he finds the treasure in it; and, having found it, he hides it, thinking that it is not without danger to reveal to everybody the secret meanings of the Scriptures, or the treasures of wisdom and knowledge in Christ. And, having hidden it, he goes away, working and devising how he shall buy the field, or the Scriptures, that he may make them his own possession, receiving from the people of God the oracles of God with which the Jews were first entrusted. And when the man taught by Christ has bought the field, the kingdom of God which, according to another parable, is a vineyard, “is taken from them and is given to a nation bringing forth the fruits thereof,”—to him who in faith has bought the field, as the fruit of his having sold all that he had, and no longer keeping by him anything that was formerly his; for they were a source of evil to him. And you will give the same application, if the field containing the hidden treasure be Christ, for those who give up all things and follow Him, have, as it were in another way, sold their possessions, in order that, by having sold and surrendered them, and having received in their place from God—their helper—a noble resolution, they may purchase, at great cost worthy of the field, the field containing the treasure hidden in itself.