Hey guys, would it be a good or bad idea to borrow from a retirement account to start my business?

I wasn't sure if this was prohibited as neither of us benefit, only the retirement accounts see a return. 

Money Mustache and other personal finance/early retirement blogs.

Build a retirement fund?

My goal is to be able to generate enough passive income to be able to "retire" in four years and pursue my dreams of traveling around the world and work part time as a fitness instructor/personal trainer(which is my passion).I'd love to meet more like minded people and to work with people who are also investing in the same locations as me!

Rates are still at epic lows, lock 'em in now and you'll be on the path to wealth and a comfortable retirement.

We were already on track to retire at 55, but BP may reel that in by a solid decade.Since joining BP, my wife and I are more excited than ever about real estate.

You can listen to it here: http://www.biggerpockets.com/renewsblog/2013/05/09/bp-podcast-017-mentors-retirement-jeff-brown/See you around the forums.

I prefer to do lending using a Solo 401K and to hold SFR outside of my retirement account.

Part of me really wants leverage to help secure my retirement.