Matthew 22:34 Hearing that Jesus had silenced the Sadducees, the Pharisees got together. 35 One of them, an expert in the law, tested him with this question: 36 "Teacher, which is the greatest commandment in the Law?" 37 Jesus replied: "Love the Lord your God with all your heart and with all your soul and with all your mind." 38 This is the first and greatest commandment. 39 And the second is like it: "Love your neighbor as yourself." 40 All the Law and the Prophets hang on these two commandments."
What is the historical context of this statement? The Pharisees counted all the commandments in the Law of Moses (Genesis-Deuteronomy) and came up to the number 613. Add the many, many rules the Pharisees made up, including the never-ending, ridiculous, burdensome man-made rules for the Sabbath day. The Pharisees made obedience into something miserable and impossible.
Jesus freed us from that, and made obedience joyful. Why is love so important? Jesus took those 613 laws and the Pharisees' rules, and reduced them to two. If we love (agape - a decision to do what is best for God and mankind), would we do what is worst for God and mankind? If we sincerely love people, would we lie, gossip, and so and do hateful things? If we truly love God, would we do things disobedient and unpleasing to Him? If we could love and hate at the same time, it is like mixing sweet water and bitter water and expecting it to taste good.
Love is the fulfillment of the law. If we love out of a desire to do what is best for others, we won't have to worry about lying, stealing, gossiping, hating our enemies, and many, many more examples of things that is NOT for the best for others.
Here are Scriptures that drive the point home:
Romans 13:8 Owe nothing to anyone, except to love one another, for the one who loves someone else has fulfilled the law. 9 For the commandments, "You shall not commit adultery, you shall not commit murder, you shall not steal, you shall not covet," and if there is any other commandment, are summed up in this statement: "You shall love your neighbor as yourself." 10 Love does not commit evil against a neighbor. Therefore love is the fulfillment of the law.
1 John 4:8 The one who does not love does not know God, because God is love.
Agape love is something that is not natural for us...how natural is it to love our enemies? Agape is divine and has to be learned from the Bible.
The Bible is an a book on loving relationships, between God and mankind. Like all relationships, God has likes and dislikes that define the relationship. God created us out of a desire to love and be loved, which describes all relationships since the Creation.