These verses are some of the most often quoted by Christians throughout history. They are popular because they sum up in two verses the Law and the Prophets. Jesus is essentially saying, if humanity lived in the manner of unselfish love, then the Law and all the teaching found in the Prophets trying to keep humanity on track, would be fulfilled. Unfortunately, sin gets in the way.
Matthew 22: 37-39
Jesus replied: “‘Love the Lord your God with all your heart and with all your soul and with all your mind.’ This is the first and greatest commandment. And the second is like it: ‘Love your neighbor as yourself.’ All the Law and the Prophets hang on these two commandments.”