one rule

In the beginning there was one commandment concerning the tree of the knowledge of good and evil. Then there were ten, written by my own hand on stone tablets. This expanded to a large number still followed by observant Jews today. In my own teaching I reversed the expansion and said that all the law and the prophets were contained in two commandments, to love the Lord your God with all your heart, soul, mind, and strength; and your neighbor as yourself. This contraction took another step at the end of my ministry when I introduced a new commandment, that my followers would love one another as I have loved them. So the commandments have come full circle and in the end there is only one. How is this a new commandment? How does it differ from the composite summary of all that has gone before?