What is God's law of love?

But, oh—how easy it is to be good here where there is no physical weakness, where there is no discord, where love is the law of life! I never knew what heaven was like. If only the ministers would tell their people of the love and thoughtfulness here, of the naturalness of this life with its continuous unbroken kindness—and no Hell, except what we make for ourselves, the world would be saved.