Depends on your starter. If you chose Blaziken or swampert then you should catch a grass type and electric type. a good grass type is ludicolo because he resists water very well. For and electric type I would suggest Manectric or Magneton.Level them up to around 40 and teach manectric or magneton thunderbolt. Teach ludicolo giga drain. I hope I helped!
The 8th Gym Leader in Pokémon Sapphire can be found in Sootopolis City.
battle them
Sootopolis City
8th gym leader
i know u have to beat a gym leader, im pretty sure it's Wallace the 8th and final.
To defeat or "beat" the 7th gym leader in Pokemon sapphire there twins and they have a solrock and a lunatone to beat them I suggest about level 40-50 water types.
you beat the gym leader
go and beat the 8th gym
go back to your fathers gym and defeat him
The gym leader in the normal gym, your character's father will give it to you after you beat him.
You need to beat the leader Norman (Your father in the game), the 5th gym leader.
Swampert.