[Diabeetus]

There are 16 division commanders of Whitebeard's crew each commanding a crew of 100. There is a grand total of 1,600 men in Whitebeard's crew.

Source for that is One Piece Yellow Data book. No, I don't have it, don't ask me to show it to you. That's the source posted up on the One Piece Wiki, most of the editors on there being members of Arlong Park who don't upload bullsh'it. So, it's a credible source of information.

Now Ace is captured and Thatch was killed by Blackbeard. Counting Marco and Jozu, that still leaves twelve commanders left to fight. I'm certain to be a commander you must be a competent fighter and incredibly strong.

Luffy's surrounded by all of these big time pirates and he's still just a rookie. He's nothing compared to these guys.