How do you go to 7th gym in sapphire?

You can't go to the 7th gym in Sapphire directly.

Here's why:

* There's no 7th gym in Ruby or Sapphire. The Hoenn region has only 8 gyms.

* The order matters: You need to defeat the gyms in a specific order before you can challenge the Elite Four.

Here's the correct order of gyms in Ruby and Sapphire:

1. Petalburg City: Normal-type gym

2. Slateport City: Water-type gym

3. Mauville City: Electric-type gym

4. Fallarbor Town: Grass-type gym

5. Veridian City: Rock-type gym

6. Ever Grande City: Flying-type gym

7. Lilycove City: Dragon-type gym

8. Sootopolis City: Psychic-type gym

After you defeat all 8 gyms, you can challenge the Elite Four!

Remember: The order of the gyms is important, so make sure to check the gym leader's type and prepare your Pokemon accordingly.