If loving God with all our heart and soul and might is the greatest commandment, then it follows that not loving Him that way is the greatest sin.
Out of a very intimate acquaintance with D. L. Moody, I wish to testify that he was a far greater pray-er than he was preacher. Time and time again, he was confronted by obstacles that seemed insurmountable, but he always knew the way to overcome all difficulties. He knew the way to bring to pass anything that needed to be brought to pass. He knew and believed in the deepest depths of his soul that nothing was too hard for the Lord, and that prayer could do anything that God could do.