For the whole law is fulfilled in one word: “You shall love your neighbor as yourself.” (Galatians 5:14 ESV)
If you were asked to sum up every command, instruction, and story you have ever told into one single word, what would it be? Mine would probably be something like foolish.
God summarizes the entirety of his commands into this one single word called love. Then to top the cake, he describes his word to us in the context of human self-love so that we might be able to understand his meaning.
You shall love your neighbor as yourself. Our primary duty toward God is to love him with all of our heart, all of our soul, and all of our mind. Adam and Eve would have been able to do this for a brief period of history before they gobbled up fruit from the first tree. But after the fall, mankind’s love toward God was replaced with a love towards self. And now the only way we can understand God’s law of love is to understand it in some sense to the way I love myself. Kind of sad and depressing I guess; yet helpful of God to teach us in this manner.