Should we buy a bow first?

My son (14) has been playing violin for 7 years and viola for 6 months. We have been renting but we are planning on buying him his own violin within the next year to take advantage of the rental credit.

He’s about to start high school orchestra I was wondering if it made sense to buy a bow now, or should we wait to get a bow when we buy the instrument. We’re going to the luthier this week and we were planning on having him try some bows and violins out, but I’m not really sure if it made sense to buy the bow before the violin. We’ve only ever rented, so purchasing is new to us. I would appreciate any advice. Thank you.