I hope I'm not too late with this and that it's a good enough explanation... 1. It basically means "Whether it is" in that context. You could say something like, "Be it rain or shine, it's always nice to go for a walk." (Something like that is, of course, for people who love getting outside whatever the weather's like - so you're really just saying, "Whether it's sunny or rainy, it's good to go outside.") 2. To "challenge" them, or respond to them forcefully. If two people get in a fight, they're said to "take each other on", so it's basically another way of saying "We will fight them/it to make sure it stops." 3. To extend and emphasize their efforts. To "step up your game" is a fairly common phrase, and it essentially just means "try harder" - so they're saying they need to put more effort into what they're doing.