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.

30. Verses 14-17 And God said, Let there be lights in the expanse of the heavens, to make a distinction between the day and the night; and they will be for signs, and for set times, and for days and years. And they will be for lights in the expanse of the heavens, to give light upon the earth; and it was so. And God made the two great lights, the greater light to have dominion over the day, and the lesser light to have dominion over the night; and the stars. And God set them in the expanse of the heavens to give light upon the earth.

No one can have an adequate understanding of what 'the great lights' are unless he knows what the underlying essence of faith is and how it develops in people who are being created anew. The very essence and life of faith is the Lord alone. In fact it is impossible for anyone who does not believe in the Lord to have life, as He Himself has said in John,

He who believes in the Son has eternal life; but he who does not believe in the Son will not see life, but the wrath of God will rest upon him. John 3:36.

[2] With people who are being created anew faith develops as follows: First of all they have no life, for life does not exist in anything evil and false but in what is good and true. Then they start to receive life from the Lord by means of faith - first by faith existing in the memory, which is factual faith, then by faith existing in the understanding, which is conceptual faith, and after this by faith existing in the heart, which is loving or saving faith. Factual faith and conceptual faith are represented in verses 3-13 by the inanimate, but faith made alive by means of love is represented in verses 20-25 by the animate. Consequently this is the first point at which love and faith deriving from it, which are called 'lights', are dealt with. Love is 'the greater light which has dominion over the day', and faith deriving from love is 'the lesser light which has dominion over the night'. And because they ought to make one the verb in the phrase 'let there be lights 'is singular and not plural.

[3] Love and faith have their place in the internal man as warmth and light do in the external, bodily man, and for this reason love and faith are represented by warmth and light. Therefore it is said that 'the lights' were set in the expanse of the heavens, that is, in the internal man - the greater light in his will and the lesser in his understanding. Yet they make their appearances in the will and understanding only as sunlight does in the objects it strikes. To the Lord alone belongs the mercy which moves the will with love and the understanding with truth or faith.