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.

155. Internal Meaning of Ezekiel, Chapter 32

Lament over those who by knowledges [scientiae] have perverted the holy things of the church. (3, 3)

1-2 They pervert all truths of the church. (3)

3-8 They fall into all falsities of evil, until they no longer see what is good and true. (3)

9-10 Those who are outside the church are horrified at their falsities. (3)

11-12 They destroy all things of the church by reasonings from the natural man. (3)

13-16 They shall be cast into hell, that they may no longer pervert truths in those who are in an affection for truth. (15)

15 In hell they will be associated with those who have profaned the holy things of the Word; (15, 17)

24-25 also with those who have falsified truths of doctrine; (15)

26-30 with those who have falsified the sense of the letter of the Word.

31-32 All of these will be with those who by knowledges [scientiae] have perverted the holy things of the church, and thus they will be separated from those who are of the church, lest they persecute them. (15)