One rule... so simple?

At Bible study tonight, we were studying Galatians 5. We were talking about how Jesus dying on the cross for us took away the need for us to adhere to any of the previous laws, which no one could keep perfectly. Jesus took all those rules away and told us to love. How simple. ONE rule. Yet-- we completely fail at keeping even that one rule. That one "law." It reminds me just how desperately we need God, when I think about all the rules that have been taken away, and how free we are. He tells us just to love, but we can't even do that apart from Him.