Today's gospel is only two verses and yet they contain probably the most difficult part of the gospel message. The man who finds the treasure and the man who finds the pearl "sells all that he has."
Jesus does not simply want to be a part of our life. He wants to be our life. As he says, "I am the way, the truth and the life." Our parents gave us simple biological life. He wants us to freely choose to hand that over to him, and he will in turn give us eternal life, (ζωή).
It is the daily, minute by minute handing over of our lives that is the difficult part. One minute we want to do God's will, the next we are either wanting God to do our will, or we have put God of the decision making process all together. We don't usually do it directly, but indirectly when we compartmentalize our faith.
This gospel reminds us that we can't be somewhat Christian. Being Christian that we must at least try to give all that we have.