Faith works by Love? What does that mean?

Many times we have heard that "Faith works by love" (Gal 5:6) and that if your love is not working then your faith won't work. But is that what Paul meant? Didn't he say "though I have all faith, so that I could remove mountains, and have not love, I am nothing."? How could you move a mountain with faith if you have not love? Maybe there is a more deeper, but obvious, meaning to "faith that works by love' that when we see it, our faith will operate more fully.