The mind is your intellect. Loving the Lord with your conscience and sub conscience mind is a willful choice that you have to make. It is to put the Lord and His ways into everything that you think....
Following the Ten Commandments, Moses added "Love the LORD your God with all your heart and with all your soul and with all your strength" in Deuteronomy 6:5.
The song talks about how the singer tells his friend all that you have to do is love the Lord, then he goes on and says that there came a time when he too fell, and his friend got to turn it around...