Whereas the Mosaic Law specified numerous situations in which the Israelites were to practice love, the Law of Christ contains comparatively few. The simple principle is enough. This is another excellent example of the essentially legal character of the Mosaic Law and the gracious character of Christ’s teachings. Jesus Christ gave us a model to follow in loving (John 13:34). Love promotes obedience.
This comment on verses 9-10 makes me wonder. There was much to emphasize about the heart and a sincere devotion in the OT. I need to think more on this.