FIRST-PERSON: Heart and soul
Indeed, the songwriter could have written "heart and whole" because that's what he was saying. When we love -- I mean really, truly love -- we love with our whole self, our entire being. There's no holding back. Isn't that how you loved when you first met the love of your life? (And hopefully still do!) There was nothing you wouldn't have done for that person. Your heart, soul, time, money, abilities -- you devoted it all to the love of your life. Your heart and your whole being were a visible expression of your love.
The original "Heart and Soul"
Isn't it funny that the man who said, "O my Lord, I am not eloquent, neither before nor since You have spoken to Your servant; but I am slow of speech and slow of tongue" (Exodus 4:10), eventually gave us some of the most beautiful prose in the Bible?
It was Moses who told the Israelites that they must "love the Lord your God with all your heart, with all your soul, and with all your strength" (Deuteronomy 6:5). Moses was saying, "Love God with your whole being, all that you are. Don't hold back anything. If you do, you won't be loving God or anyone else."
Jesus and "Heart and Soul"
When Jesus was asked, "Which is the first commandment of all?" He didn't quote the first of the Ten Commandments. He quoted Moses from Deuteronomy 6:4-5: "And you shall love the Lord your God with all your heart, with all your soul, with all your mind, and with all your strength" (Mark 12:29-30). See the fourth human dimension Jesus added to Moses' three? Jesus added the "mind" -- that we should love God with all our mental faculties as well, further expanding the totality of our love life toward God.
But then Jesus said, "This is the first commandment. And the second, like it, is this: 'You shall love your neighbor as yourself'" (verses 30-31).
What is Jesus saying with these two commandments? That loving God is the foundation for all other loves, that loving God must precede our love for others. Here are what I believe are some reasonable conclusions from Jesus' words:
1. Human love for others that is not rooted in love for God cannot be the fullest kind of love.
2. The way we love others reflects how we love God.
Jesus' first and second commandments are more than a priority list in a theological sense. They are a priority list practically speaking as well. We must love God -- understand His love in Christ and embrace that love as evidenced by our love for Him -- if we are going to be able to love others.
Is there any place in Scripture where God says, "I will love you if you do this or that"? No.
Does He say, "I will love you because you have done this or that"? No.
Indeed, God actually says, "I love you in spite of the things you have done and the things you have left undone. I love you, period."
And this is exactly how we are to love others. If we love "if or because," instead of "in spite of," then we have not yet learned to love God the way He loves us.
Heart, soul, mind and strength
Think about how you love God and see if it is reflected in how you love others:
-- With your heart: unconditionally.
-- With your soul: passionately.
-- With your mind: willfully.
-- With your strength: continually.
We should know and observe the commands of Scripture, that is true. But I daresay that if you and I love God unconditionally, passionately, willfully and continually, we will fulfill all the Law with regard to God -- and then to our neighbor. Loving God is the foundation of all other loves.