Our chachomim tell us that “We must love G-d with all our heart” refers to serving G-d with both our Yetzer Tov – our good inclination, and our Yetzer Horah – our evil inclination. In order to better understand how one can serve G-d with one’s evil inclination, let’s first explain what a Yetzer Horah and a Yetzer Tov mean and why we first get a Yetzer Tov when we become 13, while we get a Yetzer Horah at birth. Shouldn’t we get them both at the same time? Why give the Yetzer Horah a head start?
When a child is born, it has an automatic desire to satisfy its physical needs such as eating and drinking. Without this innate desire for food, the child would chas v’shalom die. This desire to satisfy our physical needs soon leads us to a love for worldly pleasures and may chas v’shalom also lead us to desire food or other pleasures forbidden to us. This desire is referred to as theYetzer Horah.
When a child reaches the age of 13, he becomes Bar Mitzvah and is now obligated to fulfill G-d’s commandments. He therefore is now given a Yetzer Tov – a desire to fulfill G-d’s commandments. This spiritual desire to serve G-d is referred to as the Yetzer Tov. When we eat with the intention of blessing G-d over the food and not just to satisfy our animalistic desires, or we exercise in order to strengthen our body so that we can better use it to serve G-d, we are using our animalistic inclination in order to serve our Maker.
And so while it is nearly impossible for a person not to have physical desires, he must learn to use all of his worldly desires with the intention of serving his Creator. One must always seek ways to serve G-d with all the skills and talents he possesses. Therefore, someone with a beautiful voice must use it as Dovid HaMelech did. This way, his entire heart – both his Yetzer Hora as well as his Yetzer Tov are occupied in the service of G-d!