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.

In Genesis 19:37; 21:26; 30:32; 40:7; Matthew 6:30; Luke 12:28, this signifies the perpetuity and eternity of a state. (Arcana Coelestia 2838)

In Psalm 2:7, this signifies in time; for with Jehovah the future is present. (True Christian Religion 101)

The expression 'even to this day' or 'today' sometimes appears in the Word, as in Genesis 19:37-38, 22:14, 26:33, 32:32, 35:20, and 47:26. In a historical sense, these expressions have respect to the time when Moses lived, but in an internal sense, 'this day' and 'today' signify the perpetuity and eternity of a state. 'Day' denotes state, and likewise 'today,' which is the current time. Anything related to time in the world is eternal in heaven, and to represent this, 'today' or 'to this day' is added. Although, in the historical sense, this appears as if the expressions only have a literal meaning, just like it says in other parts of the Word, such as Joshua 4:9, 6:25, 7:20, Judges 1:21, 26, etc. 'Today' means something perpetual and eternal in Psalms 2:7, 119:89-91, Jeremiah 1:5, 10, 18, Deuteronomy 29:9-14, Numbers 28:3, 23, Daniel 8:13, 11:31, 12:11, Exodus 16:4, 19, 20, 23, John 6:31, 32, 49, 50, 58, Matthew 6:11, and Luke 11:3.

(Odkazy: Arcana Coelestia 2838 [1-4], Genesis 47:26)