'The soul and heart' stand for a person's life. This is easy to see, but a person's life is from his will and understanding, or spiritually speaking, from love and wisdom, and so, from charity and faith.

The life of the will from the good of love, or of charity, means 'the heart,' and the life of the understanding from the truths of wisdom, or of faith, means 'the soul.' This is what 'soul and heart' means in Matthew 22:37, Mark 12:30, 33, Luke 10:27, Deuteronomy 6:5, 10:11, 11:14, 26:16, Jeremiah 32:41, and other places.

(References: Apocalypse Revealed 681)