What is the meaning of song The Promise by Girls Aloud?

The Promise is an upbeat girl power anthem about how two female friends can promise to stand up for each other. One example in the lyrics shows this: when one says "if love has left them stranded...I'll come running with my car".

The narrator is promising they’d do "just about anything" for their good friend and that there is nothing their good friend couldn’t ask "that ain’t been done."