379. It is generally recognized that there is a vital warmth in humans and in all animals, but people do not know where it comes from. People discuss it on the basis of conjecture, so if they do not know anything about the way matter is responsive to spirit, they identify the warmth of the sun as its source, some focusing on the activity of particles and some on life itself. However, since these last do not know what life is, they are just substituting one word for another.

However, once people realize that there is a relationship of responsiveness between love and its feelings on the one hand and the heart and its derivative vessels on the other, they can know that love is the source of our vital warmth. Love radiates as warmth from the spiritual sun where the Lord is and is felt as warmth by angels. This spiritual warmth, which essentially is love, is what flows into the heart and its blood by correspondence and instills both its warmth and its life. We know that we are warmed and virtually kindled by our love, depending on its intensity, and that we become sluggish and cold as that intensity decreases. We feel and see this, feeling it in a warmth throughout our bodies and seeing it as our faces flush. In contrast, we feel its loss as a physical chill and see it as faces turn pale.

Since love is our life, the heart is the beginning and ending of our life; and since love is our life and the soul brings its life through the body in the blood, the blood is called the soul in the Word (see Genesis 9:4 and Leviticus 17:14). I will be explaining later [383] what "soul" means in its various senses.