“A new command I give you: love one another.” — John 13:34So said a troubled rabbi named Jesus, 2,000 years ago in his Last Supper with his disciples. Shortly afterward he was captured, tortured and executed. The Bible says that three days later, he rose from death. The faith founded upon that resurrection claims, according to the Pew Research Center, upwards of 2 billion adherents worldwide.Ponder that. On a planet of 7 billion souls, roughly one out of every three of us is governed by that simple, difficult command. Or, at least, so it is in theory.