The heart means love. A good heart means love to the Lord and to the neighbor, while a hard or stony heart means the love of self or the world -- riches and things. When the psalmist asks the Lord to search his heart, he wants the Lord to see what it is that he loves. And we are what we love. What we eat may form our earthly body, but it's only temporary, what we love forms our spiritual body, beautiful or ugly as we have chosen. It's interesting to note that the first multi-cellular motion of our embryo is the pulsating that starts in a twist of blood vessel that is to become our heart, and the last motion of our natural body is our heartbeat. It is there for all of our natural life. And of course there is a beating heart in our spiritual bodies when we come to put them on.

A "field" in the Bible usually represents the Lord's church, and more specifically the desire for good within the church. It's where good things start, take root, and grow. When you have a desire to be a good person and to do good things, the natural first questions are "What does that mean?", "What should I do?", "What can I do?". You look for ideas, concepts, direction. Once you figure out something you want to do or a change you want to make in yourself, you seek specific knowledge. If you want to volunteer at a food pantry, say, you'd need to know whom to call, when they need help, where to go, what to bring. Armed with that knowhow, you're ready to get to work. That process could be compared to food production. You start with a field -- which is that desire to be good. Then you plant seeds -- those ideas and concepts. Those seeds sprout into plants -- the specific facts and knowledge needed for the task (easily seen in the food pantry example, but also true with deeper tasks like "being more tolerant of my co-workers" or "taking more time for prayer," or "consciously being a more loving spouse"). Finally, those plants produce food -- the actual good thing that you go and do. The Writings also say that in a number of cases a "field" represents the doctrine, or teachings, of the church. This sounds markedly different. The desire for good is emotional, a drive, a wanting; doctrine is a set of ideas. But for a church to be true, its doctrine must be centered on a desire for good, and must lead people toward doing what is good. So sound doctrine is actually closely bound up with the desire for good.