What is the origin of the idiom "heart and soul" and when to use it?

The phrase "heart and soul" is an idiomatic expression that emphasizes the entirety of a person's being, combining both the emotional and spiritual aspects. It conveys a sense of complete dedication, passion, and commitment. People use this expression to describe the complete devotion or involvement of someone in a particular activity, cause, or relationship. It signifies that they are giving their whole self to the matter at hand.