Use the pokeflute.
you cant get that move in that game
Rock Climb is not a move in the game. It wasn't a move until Diamond/Pearl/Platinum, which came out after FireRed.
There are not many glitches in Pokemon FireRed. There is one rather nasty glitch though involving roaming Legendary Pokemon. In Pokemon FireRed if a roaming Legendary Pokemon escapes battle with the move Roar it will disappear from the game rather than move to a new location.
Smeargle is a Normal type Pokemon known especially for its unique move Sketch. It cannot be caught anywhere in the wild in Pokemon FireRed and must be traded over from another game.
there is no such move as stength
RFDHDF
Move relearner? On two island near the game corner he wants tiny mushrooms or big mushrooms give it to him to make him reteach moves to your pokemon.
the move deleter is right of the Pokemon gym in fuchsia city.
Use the HM move Strength.
Since dive is not a HM in firered you will have to trade a Pokemon to a friend that has ruby, sapphire or emerald then using that game use the HM Dive to teach the move Dive to that Pokemon trade it back so firered can have that Pokemon again it will still have Dive however you cannot use it to dive underwater.
Use the pokeflute.