Justin Bieber knows just how to rub it in ... sporting some Purpose Tour merchandise just a week after he announced the cancellation of his 14 remaining shows. 

Justin was out Monday in Beverly Hills wearing some not-so-subtle yellow shorts ... aka the same shorts fans who had tickets could've also got their hands on.

It's unclear where the Biebs was off to next ... but one thing is for sure, he may want to throw a shirt on if he's headed to church.