"The bible uses the term heart to describe the bundle of desires, hopes, interests, ambitions, dreams, and affections you have. Your heart represents the source of all your motivations - what you love to do and what you care about most," (Rick Warren, Purpose Driven Life).
Catherine encourages us to open our hearts to God, to allow Him to reveal our passions, those things that we find joy doing. God is a God of love, of nurture and care. When we find out what we care about, things click for us and we serve, work, and love out of abundance.