Origen

“ The heavenly things, therefore, even the kingdom of heaven, as in a figure it is written in the Scriptures—which are the kingdom of heaven, or Christ—Himself the king of the ages, are the kingdom of heaven which is likened to a treasure hidden in the field. ”

“ And here we must inquire separately as to the field, and separately as to the treasure hidden in it, and in what way the man who has found this hidden treasure goes away with joy and sells all that he has in order to buy that field ”