The 'heavy' cross we bear, if any, I see as having to :" Love God with all your heart, all your soul, all your mind and all your strength, and love others as you love yourself." What could be harder for a fallen human being ? But as you said, we ARE supposed to serve in newness of His Life, which is SUPPOSED to make it easier for us, to obey His commandment. But as I have found, without Him right by my side, or in front of me, I cannot love that way, so it's imperative that I stick to Him like glue....