Your comment regarding your existing finances is very relevant and helpful. You need to understand that generally in personal finance circles, when a strong earning 22 year-old is looking for a loan it's usually a gross spending problem. Their car costs $1,000 /month and their bar tabs are adding up so the only logical thing to do is get a loan. Most 22-year-olds don't have a mortgage soaking up their income, or a newborn.
With all of this in mind I essentially agree with DStanley and, personally, and many people here would probably disagree, I'd stop the 401(K) contribution and use that money to pay the debt. You're still very young from a retirement standpoint, let the current balance ride and forego the match until the debt is paid. I think this is more about being debt free at 22 quickly than it's about how much marginal money could be saved via 401(k) or personal loan or this strategy or that strategy. I think at your age, you'll benefit greatly from simply being debt free.
There are other very good answers on this site and other places regarding the pitfalls of a 401(k) loan. The most serious of which is that you have an extremely limited time to pay the entire loan upon leaving the company. Failure to repay in that situation incurs tax liability and penalties.
From my quick math, assuming your contribution is 8% of $70,000 /year, you're contributing something in the neighborhood of $460/month to your 401(k). If you stopped contributing you'd probably take home a high $300 number net of taxes. It'll take around 20 months to pay the loan off using this contribution money without considering your existing payments, in total you're probably looking at closer to 15 months. You'll give up something in the neighborhood of $3,500 in match funds over the repayment time.
But again, you're 22, you'll resume your contributions at 24; still WAY ahead of most people from a retirement savings standpoint. I don't think my first retirement dollar was contributed until I was about 29. Sure, retirement savings is important, but if you've already started at age 22 you're probably going to end up way ahead of most either way. When you're 60 you're probably not going to bemoan giving up a few grand of employer match in your 20s.
That's what I would do.
Edit:
I actually like stannius's suggestion in the comments below. IF there's enough vested in your plan that is also available for withdrawal that you could just scoop $6,500 out of your 401(k) net of the 10% penalty and federal and state taxes (which would be on the full amount) to pay the debt, I'd consider that instead of stopping the prospective contributions. That way you could continue your contributions and receive the match contributions on a prospective basis. I doubt this is a legitimate option because it's very common for employers to restrict or forbid withdrawal of employee and/or employer contributions made during your employment, but it would be worth looking in to.